Bone cleaner that removes soft tissue by pressing bone stock against a cleaning element and clearing the bone stock from the cleaning element

ABSTRACT

A bone cleaning assembly ( 102, 602 ) with cleaning elements ( 690, 724, 1230, 1264 ) that remove soft tissue bone stock. The module also includes a clearing element ( 778 ) that is periodically urged against the cleaning elements to remove bone stock trapped by the cleaning elements from the cleaning elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International PatentApplication No. PCT/US2016/044386, filed on Jul. 28, 2016, which claimspriority to Provisional Patent Application No. 62/197,780, filed on Jul.28, 2015, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

This invention is generally related to an assembly capable of cleaningbone by removing the soft tissue that surrounds the bone.

BACKGROUND OF THE INVENTION

In some surgical procedures, chip-sized bone is used as filler adjacentintact bone. For example, in a spinal fusion procedure, it is known toplace a compound formed out of milled bone chips around implanted rods.The rods hold adjacent vertebrae in alignment. The compound serves as alattice upon which tissues forming the vertebrae grow to form afoundation of bone around the rods. This foundation distributes the loadimposed on the rods. Bone chips are also placed in the intervertebraldisc space or into a cage positioned in the intervertebral disc space.

Milled bone is used as a filler/growth formation lattice in theseprocedures because the material, the proteins from which the bone isformed, serve as make-up material from which the blast cells of theadjacent living bone cells can form new bone. Accordingly, in a surgicalprocedure in which it is desirable to foster the growth of new bone,milled bone, to which supplemental material is sometimes added, isemployed as filler in the spaces in which bone growth is desired. Theindividual pieces of milled bone are often referred to as bone chips.

The ideal source of bone stock for bone chips is the patient into whomthe bone chips are to be packed. This is because the patient's own boneis less likely than donor bone to be rejected by the patient's immunesystem. Accordingly, in a procedure in which bone chips are required,bone stock is often harvested from one of the patient's bones that canafford to lose a small section of bone, typically between 0.25 and 3cubic centimeters. Bone that is removed from the patient for transplantinto another part of the patient is referred to as autograft bone. Oftenthe autograph bone is harvested from the spinous process, vertebralfacets, lamina or hip.

Converting autograft bone stock into bone chips is a two part process.In the first part of the process, the harvested bone stock is cleaned toremove the ligaments, muscle and other soft tissue that is not suitablefor forming bone chips. The cleaned bone is then milled into bone chips.The Applicant's Assignee's U.S. Pat. Pub. No. US 2009/0118735/PCT Pub.No. WO 2009/061728, the contents of which are hereby incorporated byreference, discloses an electrically operated bone mill capable ofconverting bone stock into bone chips.

In a typical bone cleaning process, prior to milling the bone, surgicalpersonnel manually clean the bone. Presently, surgical personnel performthis manual process using manual tools such as scalpels, curettes and/orrongeurs. It may take 15 minutes or more for surgical personnel toperform this task.

Moreover, to perform the cleaning process, the surgical personnel mayneed to firmly grasp the bone. Exerting such force on the bone may causetearing of the gloves worn by the surgical personnel. Furthermore, thesharp cutting tools being used by the surgical personnel could cut ortear through the gloves. Such cutting or tearing through the glovescould result in the possibility that skin of the surgical personnel maycome into direct contact with the bone. This contact can result incontamination of the bone.

The Applicant's US Pat. Pub. No. US 2012/0310243/PCT Pub. No. WO2011/057088, explicitly incorporated herein by reference, discloses anumber of different assemblies for cleaning bone. One of the assembliesdisclosed in this document is a module that defines a chamber in whichthere is a fluted screw. This fluted screw is able to rotate in oradjacent the chamber. The screw is shaped so the flutes define cuttingedges. The fluted screw is encased in a shaving tube. The shaving tubehas a window through which the screw flutes are exposed. The portion ofthe shaving tube that defines the window is shaped to have its owncutting edges against the crew flutes. Bone is cleaned using the moduleof this assembly by pressing the bone against the fluted screw whilerotating the screw. The soft tissue adhering to the bone is pressedagainst the flutes. The flute cutting edges and adjacent shaving tubecutting edges function as the cooperating scissor blades. These cuttingedges cooperate to shear, cut, the soft tissue away from the bone.

The Applicant's US Pat. Pub. No. 2014/0303623/PCT Pub. No. WO2013/102134, which is also explicitly incorporated herein by reference,discloses improvements to the above-described assembly for removing softtissue from bone. One feature of the assembly disclosed in this documentis that a pivoting arm surrounds the fluted screw and shaving tubeassembly. A second feature of the assembly disclosed in this document isthat the shaving tube, not just the fluted screw, rotate. When this bonecleaning assembly is actuated: the fluted screw continuously rotates;the shaving tube periodically rotates; and the arm pivots back and fortharound the fluted screw and shaving tube. The periodic rotation of theshaving tube causes the tube to, at least momentarily, push the boneaway from where the bone may be lodged between the fluted screw and theshaving tube. The pivoting motion of the arm tumbles the individualfragments of bone stock. Collectively these actions increase the extentto which soft tissue is removed from the individual fragments of bonestock.

The above described cleaning assemblies remove tissue that surroundsfreshly harvested bone stock. However, it has been observed that a tailof the soft tissue can thread between the fluted screw and shaving tube.This tissue wraps around the inner surface of the shaving tube. If thisevent occurs, the bone stock is essentially considered caught betweenthe fluted screw and shaving tube. This means that, even when the armpivots back and forth, the arm is unable to dislodge the bone stock. Thetrapped bone stock prevents other tissue from moving against theinterface between the rotating flutes and the adjacent shaving tube.Thus, should a piece of bone stock become so trapped, in order tocomplete the cleaning process it may be necessary to stop the cleaningmodule and remove the trapped bone stock. Once the trapped bone stock iscleared from the fluted screw, the module is reactivated. However,having to interrupt the cleaning process to perform these processesreduces the utility of the cleaning module.

Furthermore owing to the nature of biological tissue, bone stock,especially freshly harvested bone stock, this material is very moist.This moisture is from the fluid such as blood, muscle and cartilage inthe soft tissue harvested with the bone stock as well as the fluidcontained in the bone itself. When the arm of the US Pat. Pub. No. US2012/0310243/PCT Pub. No. WO 2011/057088 publications presses these bonefragments against the fluted screw and shaving tube, the liquidentrained in the bone and adjacent tissue can act like an adhesive. Thematerial, collectively both the bone stock and soft tissue, cancompress. A consequence of these materials having these properties isthe bone, prior to cleaning, is known to adhere to the surfaces of arm.Once this event occurs, despite the pivotal motion of the arm, the bonestock may no longer tumble within the assembly. This tumbling isnecessary to maximize the likelihood that the individual surfaces of thebone stock fragments are pressed against the fluted screw and shavingtube assembly.

It should also be understood that bone cleaning is only one process inthe sequence of processes that need to be performed in order to placethe bone in a state in which can be used as a fill material. Asdisclosed in the incorporated by reference U.S. Pat. Pub. No. US2009/0118735, it is anticipated that after the bone stock is cleaned,the bone stock will be transferred into a bone mill. One could performthis transfer with a pair of forceps or tweezers transferring eachfragment individually. Having to perform this one at a time transferprocess can be time consuming. This would be in opposition to anobjective of against the goal of modern objective is to perform asurgical procedure as quickly as possible. This to both minimize thetime the internal tissue of the patient is exposed to the ambientenvironment and to minimize the time the patient is held underanesthesia. Furthermore, during the process of one at a time transfer ofbone fragments with tweezers or forceps even the most careful individualcan drop a fragment. Should this event occur, most likely the droppedfragment will no longer be a state in which the fragment would becontaminate free and therefore suitable for being reintroduced into thepatient as bone chips.

Therefore, a better means to transfer the plural bone stock fragments isto pour the fragments directly from the bone cleaning module into themilling module. During the process of handling and tipping the cleaningmodule of the US Pat. Pub. No. 2014/0303623 publication to perform thispour, gravity can cause the position of the arm to shift. Sometimes, asa result of this shift, the cleaned bone stock fragments may simplybecome trapped against the arm. This requires the person responsible forcleaning and milling the bone to use tweezers or forceps to complete thebone transfer process. A more serious effect of the arm shiftingposition is that arm forces fragments to pop out of the bone cleaningmodule. If the fragments land on a surface that is not consideredsufficiently sterile, the fragments will most likely be consideredcontaminated to the level at which they will no longer be suitable foruse.

SUMMARY OF THE INVENTION

This invention is directed to a new and useful assembly for cleaningbone and milling the cleaned bone to produce bone chips. The assembly ofthis invention includes a bone cleaning module that, with little manualintervention, removes soft tissue from bone stock. The bone cleaningmodule of this invention is further designed to facilitate the efficientpour of the cleaned bone stock into the complementary milling modulealso part of the assembly of this invention. The assembly of thisinvention also includes a base unit. Both the cleaning module andmilling module are removably attached to the base. Internal to the baseunit is a motor. The motor powers the moving components internal to thebone cleaning module and the bone milling module. The base has fewelectrically actuated components that must withstand the rigors of amedical sterilization process.

In some versions of the invention, the bone cleaning module isconfigured to subject the bone stock being cleaned to plural cleaningcycles. Each cleaning cycle consists of plural distinct phases. At aminimum, the bone stock is subjected to a press phase and a clear phasethat are interleaved with each other. In the press phase the bone stockis pressed against the cleaning elements. The cleaning elements are thecomponents of the cleaning module that remove the soft tissue from thebone. During the press phase, some of the bone stock may be trapped bythe cleaning elements. This is why the clear phase is executed. In theclear phase a component is urged against the cleaning elements to clearaway, cut away the trapped bone stock. In some versions of theinvention, the same component is urged against the bone stock duringeach of the press phase and the clear phase. More particularly, in manyversions of the invention wherein the same component is urged toward thecleaning element in both the press phase and the clear phase, a firstfeature of the component is urged towards the cleaning element in thepress phase and a second feature of the component is urged against thecomponent in the clear phase.

In many versions of the invention, a single cleaning cycle consists ofmore than a press phase followed by a clear phase. In some versions ofthe invention, there is a tumble phase. In the tumble phase, the bonestock is tumbled. This tumbling is performed to ensure that during acleaning processes the individual surfaces of the bone stock are each,in at least one press phase, urged against the cleaning elements. Theremay also be a sweep phase. During the sweep phase a component of thebone cleaner sweeps the bone stock to location adjacent the componentthat, during the subsequent press phase, urges the bone stock againstthe cleaning elements. In some versions of the invention a singlecleaning cycle consists of a press phase, followed by tumble phasefollowed by a clear phase and that concludes with a sweep phase. In oneconstruction of this invention of the invention, the components formingthe bone cleaning module undergo a shift phase to transition from thetumble phase to the clear phase.

In some versions of the invention, simultaneously with the bone stockbeing cleared from the cleaning elements the bone stock is gathered as aprecursor to the sweep phase.

In some versions of the invention, the cleaning elements internal to thebone cleaning element consist of a fluted screw and a shaving tube. Theshaving tube defines at least one cutting edge that is located adjacentthe cutting flutes of the fluted screw.

This invention is also directed to a bone cleaning module that includesseparate void spaces. The bone stock to be cleaned is placed in firstvoid space. This void space includes the cleaning elements that removethe soft tissue. Adjacent to and in communication with this first voidspace there is a second void space. A transfer assembly transfers theexcised soft tissue away from the cleaning elements into the second voidspace. In some versions of the invention, one or more of the cleaningelements function as part of the transfer assembly. Thus, these elementsboth remove the soft tissue from the bone and transfer the removed softtissue into the second void space.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the claims. The aboveand further features and benefits of this invention are understood fromthe following Detailed Description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of the base and cleaning module of the bonecleaning and milling assembly of this invention;

FIG. 2 is a perspective view of how the cleaning module is removablyattached to the base;

FIG. 3 is a perspective view of how a milling module of this inventionis removably attached to the base;

FIG. 4 is a cross sectional view of the interior of the assembly base;

FIG. 5 is an assembly diagram depicting how FIGS. 5A and 5B are arrangedtogether to form an exploded view of components internal to the base ofthis invention;

FIG. 6 is a perspective view of the top surface of the top plate of theshell of the base;

FIG. 7 is a perspective view of the under surface of the top plate ofthe shell;

FIG. 8 is a perspective view of the inner plate internal to the shell;

FIG. 9 is an exploded view of the motor and attached primary couplerthat are part of the base;

FIG. 10 is a cross sectional view of the motor and primary coupler;

FIG. 11 is a perspective view of the planetary gear assembly disposedaround the main spindle internal to the base;

FIG. 12 is a plan view of the arm cam internal to the base;

FIG. 13 is a plan view of the top of the tube cam internal to the base;

FIG. 14 is a perspective view of the underside of the tube cam;

FIG. 15 is an exploded view showing how the balance collar is sandwichedbetween the arm cam and the tube cam;

FIG. 16 is a perspective view how a clutch and tube coupler are disposedaround the main spindle;

FIG. 17 is an exploded view of the clutch and tube coupler;

FIG. 18 is a cross sectional view of the clutch and tube coupler;

FIG. 19 is a perspective view of the top of the clutch input ring;

FIG. 20 is a perspective view of the underside of the clutch input ring;

FIG. 21 is a perspective view of the top of the clutch output ring;

FIG. 22 is a second perspective view of the top of the clutch outputring;

FIG. 23 is a perspective view of the top of the clutch cage;

FIG. 24 is a perspective view of the underside of the clutch cage;

FIG. 25 is a cross sectional view through the clutch taken along line25-25 of FIG. 18;

FIG. 26 is a perspective view of the tube coupler;

FIG. 27 is a cross sectional view of the tube coupler;

FIG. 28 is a first perspective view of the pawl that engages the clutch;

FIG. 29 is an exploded view of the pawl and attached components;

FIG. 30 depicts the engagement of the pawl with the tab integral withthe inner coupler of the clutch;

FIG. 31 is a first perspective view of the arm coupler integral with thebase and the assembly that pivots the arm coupler;

FIG. 32 is a is a second perspective view of the arm coupler integralwith the base and the assembly that pivots the arm coupler;

FIG. 33 a cross sectional view of the arm coupler integral with the baseand the assembly that pivots the arm coupler;

FIG. 34 is an exploded view of the arm coupler and the assembly thatpivots the arm coupler;

FIG. 35 is a perspective view of the shaft of the pivot assembly of FIG.31;

FIG. 36 is a perspective view of the hat of the pivot assembly of FIG.30;

FIG. 37 is a cross sectional view of the hat;

FIG. 38 is a perspective view of the arm coupler;

FIG. 39 is a cross sectional view of the arm coupler;

FIG. 40 is a perspective view of the crank arm of the pivot assembly;

FIG. 41 is a perspective view of the rocker arm of the pivot assembly

FIG. 42 is a perspective view of the latch assembly attached to theunderside of the shell;

FIG. 43 is a plan view of the latch assembly;

FIG. 44 is a block diagram of the components that actuate the assemblyof this invention;

FIG. 45 is a perspective view of the cleaning module depicting how theshell is removably attached to the module base;

FIG. 46 is an exploded view of components internal to the cleaningmodule;

FIG. 47 is an exploded view of the components internal to the top of thecleaning module

FIG. 48 is an exploded view of the cleaning module and shell and thecomponents located above the shell;

FIG. 49 is a perspective view of the top of the bottom plate of thecleaning module;

FIG. 50 is a perspective view of the underside of the bottom plate ofthe cleaning module;

FIG. 51 is an exploded view of how the fluted screw extends through thedisk internal to the cleaning module shell;

FIG. 52 is a top plan view of the arm internal to the cleaning moduleshell;

FIG. 53 is a perspective view of the underside of the arm;

FIG. 54 is a first perspective view of the top of the arm;

FIG. 55 is second perspective view of top of the arm;

FIG. 56 is a perspective view of the top of the drive pin internal tothe cleaning module;

FIG. 57 is a perspective view of the undersurface of the drive pin;

FIG. 58 is a first perspective view of the hub integral with thecleaning module;

FIG. 59 is a second perspective view of the hub of FIG. 58;

FIG. 60 is a perspective view of the top of the lock plate internal tothe cleaning module;

FIG. 61 is a perspective view of the bottom surface of the lock plate;

FIG. 62 is an exploded view of the milling module of the assembly ofthis invention;

FIG. 63 is a perspective view of the top of the shell of the millingmodule;

FIG. 64 is a perspective view of the underside of the shell of themilling module;

FIG. 65 is a perspective view of the top of the top plate and hopper ofthe milling module;

FIG. 66 is a perspective view of the underside of the top plate andhopper of the milling module;

FIG. 67 is perspective view of the milling disk and attached couplingspindle of the milling module;

FIG. 68 is a perspective view of the top of the coupling spindle of themilling module;

FIG. 69 is a perspective view of the underside of the coupling spindleof the milling module;

FIG. 70 is a perspective view of the top of the catch tray that isfitted to the milling module;

FIG. 71 is a perspective view of the underside of the catch tray;

FIG. 72 is a cross-sectional view of the cleaning module mounted to theassembly base;

FIG. 73 depicts the relationship of the lock plate to the drive pin whenthe lock plate is in the locked state;

FIG. 74 depicts the relationship of the lock plate to the drive pininternal to the cleaning module when the lock plate is in the unlockedstate;

FIG. 75 represents how, as a result of the rotation of the arm camagainst the rocker arm, the rocker arm transitions through thesequential phases of a cleaning cycle.

FIG. 76 represents how, as a result of the rotation of the clutch camagainst the pawl, the pawl transitions through the sequential phases ofa cleaning cycle;

FIGS. 77A through 77E are diagrammatic depictions of the components ofthe cleaning module and the bone stock disposed in the cleaning moduleduring the phases of a cleaning cycle;

FIG. 78 is a cross sectional view of the milling module mounted to theassembly base;

FIG. 79 depicts how the cage of an alternative cleaning module may bedisposed around the fluted screw and shaving tube according to thisinvention;

FIG. 80 is an exploded view of the assembly of FIG. 79;

FIG. 81 is a perspective view of the underside of the module of FIG. 82;

FIG. 82 is a perspective of the drive components of the module of FIG.79;

FIG. 83 is a top plan view of the alternative cage;

FIG. 84 is a perspective view of the undersurface of the cage;

FIGS. 85A through 85G are a sequence of plan views that illustrate howthe cage engages in both rotation relative to the fluted screw andshaving tube and rotation around the longitudinal axis through the cage;

FIG. 86 is a perspective view of the inside of an alternative cleaningmodule of this invention;

FIG. 87 is a perspective view of an alternative shaving tube internal toa cleaning module of FIG. 86; and

FIG. 88 is a perspective view of an alternative hub internal to thecatchment of the cleaning module of this invention.

DETAILED DESCRIPTION I. Overview

FIGS. 1-3 illustrate the basic components of a bone cleaning and millingsystem 100 of this invention. System 100 includes a base 102 to which abone cleaning module 602 is removably attached. Bone cleaning module 602receives harvested bone stock. Upon actuation of the base 102, when thecleaning module 602 is attached, the components internal to the cleaningmodule 602 cooperate to remove soft tissue attached to the bone stock.As seen in FIG. 3, a second module, also part of system 100 and that isremovably attached to the base 102, is a milling module 902. After thebone stock is cleaned, cleaning module 602 is removed from the base 102and milling module 902 is attached to the base. The cleaned bone stockis transferred from the cleaning module 602 to the milling module 902.The assembly base 102 is again actuated. This results in the componentsinternal to the milling module 902 converting the cleaned bone stockinto smaller sized bone chips. The bone chips are available for use asfill in surgical procedure.

Internal to the base 102 is a motor 140 (FIG. 4). When a module 602 or902 is connected to the base 102, a number of the moving componentsinternal to the module are connected to the motor 140. By depressing aswitch 588 or 590 on the base 102, the motor 140 is actuated. Theactuation of the motor 140 results in the like actuation of thecomponents internal to the module 602 or 902, that, respectively, cleansor mills the bone.

II. Assembly Base

The assembly base 102, as seen by reference to FIGS. 2 and 3, includes ashell 104 that is the outer body of the base. Shell 104 is formed have apedestal 106 that, in terms of a gravity reference plane, is thebottommost portion of the shell. A neck 112 extends upwardly frompedestal 106. In cross sectional planes parallel to the gravityreference plane, neck 112 is smaller in area than the pedestal 106. Theperimeter of the neck 112 is located inward of the outer perimeter ofthe pedestal. Shell 104 is further formed to so that pedestal 106 has aface panel 108 that tapers inwardly from the widest portion of thepedestal to is shaped to have a face panel 108 to neck 112.

Above the neck 112, shell 104 is shaped to have a head 114. The shell104 is shaped so that the head 114 projects outwardly from the neck 112.In the depicted version of the invention, both the neck 112 and head 114appear in cross section to be in the shape of a truncated oval. (Thecurved side sections of the neck and head each subtend an arc of lessthan 180°. A top plate 122 is the topmost structure panel of the head114 and, by extension, of shell 104. Top plate 122 is recessed inwardlyapproximately 5 mm from the adjacent outer perimeter of the head 114.The top plate 122 has a rim 116 that extends circumferentially aroundand downwardly from the planar top surface of plate 122. A step 115 thatextends inwardly from the outer surface of the head 114 to the to therim functions as the transition surface between the outer perimeter ofthe head 114 and the top plate rim 115.

The top plate 122 is further formed so there are four rectangularopenings 118 in rim 116, openings identified in FIGS. 6 and 7. Openings118 are located in the sections of the rim 116 adjacent the front andback edges of the top plate 122. The front edge of the top plate isunderstood to be the edge above shell base panel 108. The back edge isthe edge furthest from the base panel 108.

Top plate 122 also has two openings, openings 124 and 126. Openings 124and 126 are both centered on the major axis that extends side to sideacross the plate 122. Opening 124 is spaced to be approximately 1 cmaway from the minor axis across the plate. The minor axis is the axisthat extends from the midpoint of the panel front edge to the midpointof the panel back edge. Opening 126 is located on the side of the plateminor axis opposite the side closest to opening 124. Opening 126 islocated closer to the adjacent curved sides of the top plate 122 thanthe minor axis. Rim 116 is also shaped to define a slot 119 identifiedonly in FIG. 43. Slot 119 extends through the curved side of the rim 116located adjacent opening 126.

The top plate 122 is further formed to have sleeves 123, 127 and 128that project downwardly from the undersurface of the planner portion ofthe plate 122. Sleeve 123 extends downwardly from the planar portion ofthe plate below opening 124. Sleeves 127 and 128 are concentric andextend downwardly from the planar portion of the plate below opening126. Sleeve 127 is the inner most sleeve, the sleeve that defines a borethat extends inwardly from opening 126, (bore not identified). Sleeve128 is the outermost sleeve and is spaced radially outwardly from sleeve127. The top plate 122 is further formed so that sleeve 128 projectsdownwardly from the top plate 122 than sleeve 127. A number of posts 129are also seen projecting downwardly from the undersurface of the topplate 122, two posts identified. The free ends of the posts are shown ashaving bores, (bores not identified). The bores are present forreceiving fasteners as discussed below.

Two support members are statically mounted to the inside of shell 104. Afirst one of the support members is a motor mount 132 seen only in FIG.4. Motor mount 132 is generally plate like in shape and is mounted inthe neck 112 so as to be relatively close to the pedestal 106. The motormount 132 is formed with a large through hole 134.

A second support member, inner plate 150, is disposed in the shell head114. Not identified is the step internal to the shell on which the outerperimeter of the inner plate 150 is seated. Plate 150, as seen best inFIG. 8, has a planar base 152. The plate 150 is further formed to havetwo voids, voids 156 and 162, that extend downwardly from openings inthe base 152. The inner plate 150 is shaped so that the void 156 isapproximately in the shape of triangle with rounded vertices. Innerplate 150 is formed so that void 156 is located below top plate opening126. The base of void 156 is defined by a panel 160 that is locatedbelow base 152. A web 158 that extends downwardly from the base toconnect the panel to the base defines the perimeter of the void 156.Void 162 is located to be coaxial with top plate opening 124. A boss 166located below plate base 152 defines the base of void 162. A web 164,also part of plate 150, that extends between the plate base 152 to theboss 166 both holds the boss to the rest of the plate 150 and definesthe outer perimeter of void 162.

Motor mount 132 and inner plate 150 are both seen as having a number ofopenings, through bores and closed end bores. Some of the openings andbores are surrounded by counterbores. Some of these bores opendownwardly from circular islands that extend upwardly from the topdirected surfaces of the motor mount 132 and plate base 152. Theseopenings, bores, counterbores and islands are not identified. It shouldbe understood that these bores and counterbores receive the pins andfasteners that hold the below discussed components of the assembly base102 to the motor mount 132 and the inner plate 150. Some of the openingsin the inner plate 150 are positioned to align with the posts 129 thatextend downwardly from the top plate 122. Fasteners, (not illustrated)that extend through openings in the inner plate 150 and into theadjacent bores in the posts 129 hold the inner plate to the posts 129.Posts 129 thus connect the inner plate 150 to the top plate 122 so thissub-assembly, including the component mounted to the plate 122 and 150can be fitted in the shell 104 as a single unit.

The motor 140 is mounted to the downwardly directed surface of the motormount 132. Fasteners, not illustrated, hold the motor 140 to the mount132. Motor 140 has a shaft 142, seen only in cross section in FIG. 10,that extends through an opening that extends through the mount 132. Theopening through which shaft 142 extends is larger in diameter that theshaft. The motor 140 is mounted in shell 102 so that the motor shaft iscoaxial with the opening 124 in the shell top plate 122.

Motor shaft 142 is connected to a gear train 144 the outer shell ofwhich is seen in the drawings. The gear train 144 is seated in opening134 internal to the motor mount 132 so as to be disposed over theportion of the motor 140 located immediately below the opening 134. Geartrain 144 typically consists of a planetary gear assembly that stepsdown the speed of the rotational motion of the motor shaft 142. Therotational motion of the gear train is output through a shaft 145 thatextends upwardly from the outer shell of the gear train. In one versionof the invention, motor 140 is designed so that when actuated, rotate ata speed of the motor shaft 142 between 2500 to 5500 RPM. Gear train 144is configured so that the speed ratio between the motor shaft 142 andgear train shaft 145 is between 5:1 and 90:1.

The base of gear train 144 is attached directly to face of the housingof motor 140. The base of the gear train 144 is thus seated in theopening in the motor mount 132 through which the motor shaft 142extends. The top surface of the gear train 144 is mounted to theundersurface of boss 166 integral with plate 152. In the illustratedversion of the invention a plate 151 is located between the top of thegear train 144 and the underside of the boss 166. The plate 151 may beformed from elastomeric material to cushion the vibrations of the motor.Fasteners 147, one fastener identified in FIG. 4, that extends throughplate 151 into the top of the gear train holds the plate to the geartrain. Gear train 144 has a shaft 145 that extends through an opening inthe boss 166 so as to extend into void 162 internal to the plate 150.The gear train shaft 145 is generally cylindrical in shape. A key 146,identified in FIG. 9, extends outwardly from the cylindrical surface ofthe shaft 145. The key 146 extends longitudinally along the shaft 145.

A spindle 170, seen best in FIGS. 9 and 10, is mounted to the gear trainshaft 145 to rotate in unison with shaft 145. Spindle 170 includes acylindrical base 172. A cylindrical trunk 176 extends upwardly from thebase 172. Trunk 176 is coaxial with the base 172 and has a diameter lessthan that of the base. Adjacent where the trunk emerges from the base172, spindle 170 is shaped to have a step 174 that extends around thetrunk. Above the trunk 176, the spindle has a neck 180. Neck 180 iscoaxial with and smaller in diameter than the trunk 176. A step 178,thus extends circumferentially radially outwardly from the bottom of theneck 180 so as to function as the transition surface between the trunk176 and the neck 180. The topmost portion of the spindle is head 182.The head 182 is coaxial with and has a smaller diameter than the spindleneck 180.

The spindle 170 is further formed to have a closed end bore 184 thatextends upwardly from the bottom of base 172. Bore 184 is coaxial withthe base 172. An indentation 186 extends inwardly from the outer surfaceof the spindle neck 180. Spindle 170 is further formed so a bore 188extends longitudinally through the spindle head 182. In the illustratedversion of the invention, bore 188 is centered on axis that isperpendicular to the center radial line that extends inwardly throughindentation 186 to the longitudinal axis of the spindle 170.

Spindle 170 is seated over the gear train 144 so the gear train shaft145 is seated in spindle bore 184. Key 146 seats in a slot 185 internalto the spindle that extends outwardly from outer perimeter of bore 184.This key in slot arrangement ensures that the gear train shaft 145 andspindle 170 rotates as a single unit.

A gear 190 is disposed around spindle trunk 176 to rotate in unison withthe spindle 170. The gear 170 sits on step 174. The teeth of the gear190 are located both above the spindle base 172 and radially outwardlyfrom step 174 (gear teeth not illustrated).

A primary coupler 194 is mounted to spindle 170. The primary coupler 194includes a cylindrical base 196. A pin 198 extends upwardly from the topof base 196. Also disposed on the top of base 196 are three equangularlyspaced apart teeth 202. Each tooth 202 is an elongated member thatprojects radially outwardly from the pin 198 and extends upwardly fromthe top of the base 196. Primary coupler 194 is formed so that pin 198projects above the teeth 202.

The primary coupler 194 is further formed to have a bore 204 thatextends upwardly from the bottom of base 196. Bore 204 has a diameterthat allows the spindle head 182 to closely slip fit in the in the bore204. Bore 204 opens into a closed end bore 206 that extends towards thetop of the base 196. The primary coupler 194 is formed so that bore 206has a diameter that is less than the diameter of bore 204. Moreparticularly, the coupler 194 is formed so that bore 206 has a diameterthat is less than the diameter of the head 182 of stem 170. Coupler 194is further formed to have two diametrically opposed oval shaped openings208 that extends inwardly from the outer cylindrical surface of base 196(one opening 208 seen in FIG. 10). Openings 208 extend into bore 204.

The primary coupler 194 is fitted to the rest of the assembly base 102so that spindle head 182 is disposed in coupler bore 204. A pin 210extends through coupler openings 208 and into bore 188 internal to thespindle head 182. Pin 210 holds the primary coupler 194 to the spindle170 so the coupler rotates in unison with the spindle and is able tomove longitudinally along the longitudinal axis through the spindle. Theprimary coupler is positioned so that the top of the coupler base 196extends through top plate opening 124. Coupler pin 198 and teeth 202 arelocated above the shell top plate 122.

A spring 212, seen in FIG. 5A, is disposed in coupler bore 208. Spring212 provides a bias force that normally displaces the coupler so thecoupler pin 198 and teeth 202 are spaced away from the shell top plate122. The upward movement of the coupler 194 is limited by the portion ofthe coupler that defines the bottom of opening 208 abutting pin 210.Downward movement of the coupler is limited by the step internal to thecoupler defining the transition from bore 204 to bore 208 abutting thetop of spindle head 182

A secondary gear train 220, the components of which are best seen inFIGS. 5A, 5B and 11, is disposed around the neck 180 of spindle 170. Thesecondary gear train 220 includes a ring gear 222 disposed in void 162internal to inner plate 150. The gear 222 is positioned so that theouter surface of the gear is disposed against the inner surface of web164. The teeth of the ring gear, (teeth not identified) extend inwardlytowards the center of void 162. Not illustrated is the snap ring that isdisposed around and above the outer perimeter of the ring gear 222. Thesnap ring protrudes outwardly from a groove in web 164. The snap ringholds ring gear 222 in void 162.

Gear train 220 also includes a first set of planet gears, gears 224.Gears 224 are rotatably mounted to a carrier 226 by pins 225. Gears 224engage both gear 190 and the teeth of ring gear 222. Carrier 226 has itsown sun gear 228 that surrounds the neck 176 of spindle 170. The innerdiameter of sun gear 228 is spaced radially outwardly from the spindle170.

Three planet gears 230, also part of the secondary gear train 220,extend between ring gear 222 and sun gear 228. Planet gears 230 arerotatably mounted to the below described arm cam 234 by pins 231. Thesecondary gear train is designed to cause the arm cam and attachedcomponents to rotate at a speed less than that of the rotation speed ofthe spindle. In some versions of the invention, the speed ratio betweenspindle 170 and the arm cam 234 is between 12:1 and 24:1.

Arm cam 234, seen best in FIG. 12, is a generally disc shaped component.The arm cam 234 is formed with a center opening 236. Opening 236 isdimensioned so as to have a diameter greater than that of the spindleneck 182. The arm cam has two lobes. An outer lobe, lobe 238, has anouter perimeter that is spaced relatively far away from the center ofcam 234. Outer lobe 238 subtends an arc that extends more than 180°around the outside of the cam 234. In some versions of the invention theouter lobe subtends an arc of between 190 and 240°. The second lobe isinner lobe 242. Inner lobe 242 has an outer perimeter that is spacedradially inward from outer perimeter of the outer lobe 238. Inner lobe242 subtends an angle around the cam 234 between 20 and 60°. Notidentified are the transition surfaces between each end of the outerlobe 238 and the adjacent end of the inner lobe 242.

The arm cam 234 is formed with two sets of through bores that extendside to side through the cam and that are spaced radially outwardly fromthe opening 236. A first set of bores are three equangularly spacedapart bores 244. Bores 244 receive the pins 231 that rotatably holdplanet gears 230 to the arm cam. A second set of bores are threeequangularly spaced apart bores 245. Bores 245 are larger in diameterthan bores 244 angularly offset from bores 244 and spaced slightlyradially outwardly from bores 244. Bores 245 receive the fastening pinsthat hold the below described tube cam 252 to the arm cam 234 (fasteningpins not illustrated).

The tube cam 252 now described by reference to FIGS. 13 and 14 ismounted the arm cam 234. The tube cam 252 is a single piece componentthat includes a ring shaped skirt 254. A rim 256 is disposed above theskirt 254 and extends radially outwardly from the skirt. Tube cam 252 isformed so rim 256 has inner and outer lobes 258 and 262, respectively.Inner lobe 258 has an outer surface 260 that, in terms of radialdistance, is located relatively close to the center of the cam. Theinner lobe 258 subtends an arc that subtends an arc of greater than 180°around the cam 252. In some versions of the invention the inner lobe 258subtends an arc between 185° and 205° Outer lobe 262 is shaped to havean outer surface 264 located further from the center axis of the cam 252than surface 260 of the inner lobe 252. Tube cam 252 is formed so thatthe cam surface 264 subtends an arc of between 40° and 140° around thecenter of the cam. Not identified are the transition surfaces betweenouter surface 260 and outer surface 264.

Tube cam 252 is formed so that the skirt 254 and rim 262 collectivelydefine an opening 266 that extends through the center of the cam. Thetube cam is further formed to define a step 268 that projects into andextends circumferentially around opening 266. Step 268 is located belowthe top surface of rim 262. Three equangularly spaced apart bores 270,identified in FIG. 14, extend from the bottom of skirt 254 to the top ofstep 268. Upon assembly of base 102, tube cam bores 270 are inregistration with arm cam bores 245. Bores 270 receive the fasteningpins that hold the shave cam 252 to the arm cam 234.

As best seen in FIG. 15, a balance collar 246 is sandwiched between thearm cam 234 and the tube cam 252. The balance collar 246 includes acenter ring 247. Assembly 102 is constructed so that the skirt 254 isdisposed in and rotates within the void defined by ring 247. Four tabs248, two seen in FIG. 15, project outwardly from the center ring 247. Afastener 249, three fasteners identified, extends through each of thetabs 248. The fasteners 249 are secured to base 152 of the inner plate150. Fasteners 249 thus hold the balance collar 246 static to theassembly base 102. Tabs 248 and fasteners 249 are located radiallyoutwardly of the arm cam 234. Thus, the presence of the static balancecollar 246 does not inhibit the rotation of the arm cam 234 and the tubecam 252.

A clutch assembly 278, seen best in FIGS. 16-18, is disposed above thetube cam 252 around the spindle 170. In FIGS. 16 and 18, the arm cam234, the shaving cam 252 and the gear assemblies below the arm cam 234are not seen to simplify the Figures.

The clutch assembly 278 includes an input ring 280. The input ring 280,seen best in FIGS. 19 and 20, has a tubular shaped stem 282. Stem 282 isformed with a through bore 284 and is dimensioned to tightly fit aroundthe neck 180 of spindle. A slot 285 extends outwardly from the innersurface of the stem 282 that defines bore 284. Slot 285 is thuscontiguous with bore 284. Input ring 280 is further formed to have ahead 286 that extends radially outwardly from the top of stem 282. Head286 is shown to have a ring (not identified) that protrudes outwardlyfrom the outer surface of the head. This ring provides mechanicalstrength to the input ring 280. The head 286 is formed to define in thecenter of the head are circularly shaped void 288. Void 288 iscontiguous with and larger in diameter than bore 284 that extendsthrough stem 282. The head 286 is further formed so that as to have arecessed surface 290 that surrounds the opening into bore 284

The input ring 280 is fitted to spindle 270 so the ring stem 284 isdisposed over the spindle neck 180. Stem 284 is disposed within opening236 of the arm cam 234. The lower portion of the ring head 286 isdisposed within opening 266 of the tube cam. A key 181, identified onlyin FIG. 18, extends outwardly from the spindle neck 180. Key 181 seatsin slot 285 internal to the input ring 280. This key-in-slot arrangementensures that spindle 170 and the clutch output ring rotate as a singlepiece unit.

An output ring 320, also part of clutch 278, seen best in FIGS. 21 and22, is disposed in the input ring void 286 and projects above the inputring 280. The input ring 320 has a circular base 322. A generallytube-shaped sleeve 324 extends upwardly from the outer perimeter of base322. While the inner and outer surfaces of sleeve 324 are generallycylindrical in shape, these surfaces are not completely cylindrical.Output ring 320 is formed so as define four equangularly spaced apartflats 326 along the outer surface of sleeve 324, two flats identified inFIGS. 21 and 22. Flats 326 are located within the circular area definedby the curved outer surface of the sleeve 324. Relative to thetop-to-bottom longitudinal axis through the outer ring 320, each flat326 subtends and angle between 50° and 90°. The outer ring 320 isfurther formed to have a circular lip 328 that is disposed above sleeve324. The ring 320 is formed so that lip 328 projects radially outwardlybeyond the outer surfaces of sleeve 324.

The output ring 320 is further formed so there is an opening 330 in base322. Opening 330 is of sufficient diameter so that, when the assemblybase 102 is assembled, there is a clearance between the outer surface ofthe spindle head 182 and the surface of ring base 322 that defines theouter perimeter of the opening 330. Sleeve 324 and lip 328 collectivelydefine a void 332 that is contiguous with opening 330. The base 322 isfurther formed to have a recessed surface 334 in the top surface of thebase. Recessed surface 334 extends circumferentially around opening 330and is defines the lowest section of void 332.

Output ring 320 is further formed to have two notches 336 that extendradially outwardly from the inner surfaces of sleeve 324 and lip 328.Notches 336 extend longitudinally from the top face of ring 320 throughthe ring and partially through the sleeve 324. The notches 336 arediametrically opposed to each other relative to the longitudinal axisthrough the outer ring 320. The outer ring is further formed so lip 328is shaped to define a step 338 that extends inwardly around the innerperimeter of the lip. Step 338 is located below the top directed face oflip 328. The notches 336 intersect the step 338.

Two coaxial bores 335, identified only in FIG. 21, extend laterallythrough the lip 328 of the output ring 320. Bores 335 intersect step338. When the clutch 278 is assembled, a pin 339 is seated in each ofthe bores 335. Each pin 339 has a head that is located radiallyoutwardly from the adjacent cylindrical surface of lip 328 of the outputring 320.

A cage 294, seen best in FIGS. 23 and 24, also part of clutch 278, isdisposed between input ring 280 and output ring 320. The cage 294includes a ring 296. A generally tube shaped skirt 298 extendsdownwardly from the ring 296. Cage 294 is formed so the inner surface ofskirt 298 is flush with the inner surface of ring 296. The outer surfaceof skirt 298 is located radially inwardly from the outer perimeter ofring 296. The cage is further formed so there are four equangularlyspaced apart slots 302 in the skirt 298, two slots identified. Each slot302 extends upwardly from the base of the skirt 298, the end of theskirt opposite the end adjacent ring 296. Each slot 302 is centeredalong a major axis that is parallel to the top to bottom longitudinalaxis through the cage 294. The cage 294 is formed so that slots 302terminate at a location spaced below where the skirt 298 extendsdownwardly from ring 296.

Cage 294 is further formed so a tab 304 projects outwardly from theouter perimeter of the ring 296. Two pins 306, identified in FIG. 23,extend upwardly from the top facing surface of ring 296. Pins 306 arediametrically opposed to each other relative to the longitudinal axisthrough the cage 294. Not identified are closed end bores in the topsurface of the ring in which the pins are seated.

In some versions of the invention, cage 294 is formed from twocomponents that are assembled together to function as a single pieceunit. This is facilitates the selective positioning of the tab 304relative to the pins 306 during the manufacturing process.

When clutch 270 is assembled, the output ring 320 is seated in void 288of the input ring 280. Base 322 of the output ring is seated on a lowfriction washer 293 seated over recessed surface 290 of the input ring280. The presence of washer 293 facilitates the relative rotationmovement of the input ring 280 to the output ring 320. The cage skirt298 is disposed between the head 286 of the input ring 280 and sleeve324 of the output ring. Each skirt slot 302 is adjacent one of the flats326 formed in the outer surface of the outer ring sleeve. The componentsforming the clutch are dimensioned so that the cage 294 can rotaterelative to both the input ring 280 and the output ring 320.

A cylindrical pin 305 is disposed in each of the slots 302 formed inclutch cage 294, two pins identified in FIGS. 17 and 25. Pins 305 have acommon diameter that is less than the wall thickness of the cage skirt298. Each pin 305 thus projects inwardly toward from the skirt 298 tothe adjacent flat 326 formed in the output ring 320.

A spring 340, one identified in FIG. 17, also part of clutch 270,extends between each pin 306 and adjacent pin 339, one spring identifiedin each of FIGS. 16 and 17. Springs 340 normally hold the cage so thateach slot 302 is adjacent the end of the adjacent flat 326 as seen inFIG. 25. As a result of the cage 294 being in this orientation, each pin305 is essentially wedged between the inner surface of the input ringhead 286 and the adjacent flat 326. When the input ring 280 undergoescounterclockwise rotation in the view depicted in FIG. 25, pins 306transfer this rotation to both the cage 294 and the output ring 320.When the output ring 320 so rotates, clutch 278 is considered to be inthe engaged state.

Clutch 278 drives a tube coupler 348 now described by reference to FIGS.26 and 27. Tube coupler 348 includes a cylindrical pedestal 350.Pedestal 350 has an outer diameter that is greater than the innerdiameter of the sleeve 123 below top plate opening 124. The outerdiameter of the pedestal is also such that the pedestal can slip fitwithin void 332 defined by the inner cylindrical surface of sleeve 324of the output ring 320. A tube shaped head 352 extends upwardly frompedestal 350. A circular step 351 defines the transition between thecoupler pedestal 350 and head 352. A sleeve like low friction bushing358 is shown disposed around the inner cylindrically shaped wall of head352. Three equangularly spaced apart teeth 353 extend upwardly from thecircularly shaped top face of coupler head 352, one tooth identified.

The tube coupler 348 is formed to have a bore 354 that extends upwardlyfrom the bottom of pedestal 350. Not identified is the taperedcounterbore that forms the opening into bore 354. Bore 354 opens into abore 356. Bore 356 is coaxial with and has a smaller diameter than bore354. Bushing 358 it is understood is disposed against the inner surfaceof coupler head 352 that defines bore 356. A small lip 357 protrudesinto bore 356. Lip 357 is located near the bottom of the coupler head352. Lip 357 is the structural feature of the tube coupler that supportsbushing 358 in bore 356.

Two axially aligned pins 390 extend radially outwardly from opposedsections of the coupler pedestal 350. Not identified are the boresinternal to the pedestal in which the pins are seated. The pins 390 aredimensioned to seat in notches 336 internal to the output ring 320. As aresult of the seating of pins 390 in the output ring notches 336, tubecoupler is connected to clutch 278 to both rotate in unison with theoutput ring 320 and move longitudinally relative to the ring 320.

Assembly base 102 is constructed so that the tube coupler 348 is able toboth rotate in and move longitudinally in sleeve 123 integral with theshell top plate 122. A spring 394, identified in FIGS. 17 and 18,extends between recessed surface 334 of the output ring 320 and the stepinternal to the tube coupler between bore 354 and bore 356. Spring 394biases the tube coupler 348 so teeth 353 are normally urged away fromthe shell top plate. The abutment of the external step 351 above thecoupler pedestal 350 against the overlying end of sleeve 123 limits theupward movement of the tube coupler 348.

The primary coupler 194 extends through bushing 358. Owing to thedimensioning of the components of base 102 and the low friction natureof the bushing 358, primary coupler 194 is able to both rotate relativeto and move longitudinally within bushing.

A pawl 396, seen best in FIGS. 28 and 29, selectively blocks therotation of the clutch cage 294 to transition clutch 270 between theengaged and disengaged states. The pawl 396 has a body 398 that isformed as to have a longitudinal axis that is curved. The corners of thebody 398 are rounded. Pawl body 398 is further formed to have a groove402 that extends longitudinally along the body. Groove 402 extendsinwardly from the outer side of the body 398, the side of the body thatis directed away from the tube cam 252. The groove 402 forms an openingin one end of the body 398, opening not identified. As the groove 402extends from the end of the body in which the groove forms an opening,the depth of the groove decreases. The pawl body 398 is further formedto have a notch 404. Notch 404 is located in the end of the bodyopposite the end of the body from which groove 402 extends. By referencethe gravity reference plane, notch 404 is located below groove 402.

Pawl body 396 is further formed to have two bores that extend top tobottom through the body. A first bore, bore 406, extends through thebody adjacent the end of body from which groove 402 extends. Bore 406intersects groove 402. The second bore, bore 408, is located inward ofthe end of body opposite the end in which bore 406 is formed. Bore 408intersects notch 404.

The pawl 396 is further formed so as to have a finger 410. Finger 410extends outwardly from inner side of the body 398. The pawl 396 isformed so that the finger 410 is located above notch 404.

A roller 412 is disposed in pawl notch 404. The roller 412 is rotatablyheld to the pawl body by a pin 414 that is seated in bore 408 andextends through the roller.

The pawl 396 is pivotally mounted to a pin 416 that extends upwardlyfrom base 152 of inner plate 150. A spacer 417, seen only in FIG. 5B,holds the pawl above the base 152. In the depicted version of theinvention, pin 416 extends through the spacer 417. Spacer 417 is mountedto the inner plate 150 to be static relative to the plate.

A torsion spring 418, seen only in FIG. 29, is seated in groove 402.More particularly, the helically center portion of spring 418 is seatedaround the section of pin 416 that extends through pawl groove 406. Oneleg of the torsion spring 418 is disposed against the surface of thepawl body 398 that defines the base of groove. The opposed leg of thetorsion spring 418 bears against an adjacent surface of inner plate web164.

Owing to the presence of spacer 417, pawl 396 is positioned so that thepawl roller 412 is positioned so that the roller 412 is in the sameplane as the tube cam 252. Pawl finger 412 is the same plane in whichtab 304 integral with clutch 270 rotates. Torsion spring 418 places aforce of the pawl that forces roller 412 against the outer surface oftube cam 252. The components forming the assembly base 102 aredimensioned so that when the roller 412 rides against the cam inner lobe258, finger 410 is disposed in the space through which tab 304 rotates.When the rotation of cam causes the outer lobe 262 to rotate againstroller 412, the force of the cam 252 overcomes the force of spring 422.Pawl 396 pivots around pin 416. As a result of this pivotal movement,finger 410 moves away from the space through which tab 304 rotates.

When pawl 398 is spaced from tab 304, springs 340 place a torque on theclutch cage to hold the cage in the position depicted in FIG. 25.Specifically, the pins 305 are held adjacent the flats 326. Owing towhere the pins 305 are positioned between the input ring 280 and theoutput ring 320, the pins become wedged between these two components,the input ring and the output ring. Pins 305 are thus blocked fromrotational motion. The pins 305 are also understood to be in frictionalcontact with the inner cylindrical surface of the head 286 of the inputring 280. When the input ring 280 is rotated counterclockwise whenviewed from the perspective of FIG. 25, the rotation of the input ring280 is, owing to the frictional contact, transferred to the pins 305.Pins 305 thus rotate with the input ring. Owing to the pins 305 beingwedged against the output ring 320, the pins force the output ring intoa like counterclockwise rotation. When the clutch is in this state, theclutch is on the engaged state.

There are times during the operation of the assembly 100 when the pawl398, as seen in FIG. 30, presses against the tab 304 integral with theclutch cage 294. As a result of this pawl against tab abutment, theclutch cage is blocked from further rotation. When this even occurs, therotation of the pins 305 relative to the output ring 320 shifts.Specifically, the cage 294 and pins move to a rotation orientation,relative to the inner output ring 320 that is clockwise to the rotationorientation seen in FIG. 25. As a result the pins are no longer wedgedagainst the output ring. When the pins 305 are in this rotation, thepins do not transfer the rotational movement of the input ring 280 tothe output ring 320. The clutch is in the disengaged state.

The assembly base 102 also includes a cage driver 420. Cage driver 420pivots the cage 764 internal to the cleaning module 602. The cage driver420 includes a shaft 422 seen best in FIG. 35. Shaft 422 is a singlepiece component with a number of coaxial sections that have differentdiameters. At the bottom of shaft 422 there is a foot 424. Foot 424 isformed to have two parallel flats 423 (one seen) that are locatedinwardly of the outer cylindrical surface of the foot. A trunk 428 islocated immediately above the foot 424. Trunk 428 has a diameter that islarger than the diameter of the foot 424. A collar 430, also part ofshaft 422, extends circumferentially around and radially outward from aportion of trunk 430. Shaft 422 is formed so that the trunk 428 extendsoutwardly from the shaft starting at a location slightly above themid-level of the shaft. The top of the collar 430 is located below thetop of the trunk 428. The shaft 422 is further formed to have a head 432that extends upwardly from the trunk 428.

A closed end bore 436 extends upwardly from the bottom of foot 424.Flats 423 and bore 436 are present to facilitate assembly anddisassembly of the base 102 and are otherwise not relevant to thisinvention,

The shaft 422 is further formed to have an elongated oval shaped hollow438 that extends side-to-side through the shaft. Hollow 438 is centeredon a major axis that is perpendicular to the top-to-bottom longitudinalaxis through the shaft 422. Shaft 422 is formed so that the hollow 438extends across the whole height of the collar 430. Hollow 438 alsoextends a short distance into the portions the shaft trunk 428 thatextends below and above the collar 430. The hollow 438 is closed ended;the hollow does not extend laterally through the trunk 428 and collar430. The shaft is further formed with a circular through bore 440. Bore440 is formed in the shaft head 432 and located immediately above thetrunk 428. The bore 438 is centered on an axis that is perpendicular toand intersects the longitudinal axis through the shaft 422.

Shaft 422 is disposed in the base 102 so foot 424 and torso 428 extendthrough panel 160 that is part of inner plate 150. The foot and leg 424extend through concentric openings formed in panel 160. A bushing 444formed from acetyl or other low friction material extends around the leg424 and the adjacent opening defining surface of the plate 150. Bushing444 facilitates the rotation of the shaft 422.

A crank 448 that extends outwardly from the shaft 422 sets therotational orientation of the shaft 422. The crank 448 includes acircular ring 450. Ring 450 has an inner diameter that allows the crankto tightly fit over the collar 430 integral with the shaft 422. Twoparallel, spaced apart overlapping tabs 454 extend radially outwardlyfrom ring 450.

The crank 448 is further formed so ring 450 has two opposed recessedsteps 452. Steps 452 are recessed inwardly relative to the opposed topand bottom faces of the ring 450 and surround the through center opening454 that extends axially through the ring. Crank 448 is further formedto have a slot 456. Slot 456 extends radially outwardly from thecylindrical inner surface of the ring that defines opening 454. Slot 456is thus contiguous with the center opening 454. The crank 448 is formedso that slot intersects the surfaces of steps 452. Each one of the cranktabs 454 is formed with an opening 458 that extends through the tab. Theopenings 458 are located slightly inward of the outer ends of the tabs458. Openings 458 are coaxial.

Crank 448 is seated around shaft 422 so that the crank slot 456 isaligned with hollow 438 internal to the shaft. A key 460 extends fromthe hollow 438 to slot 456. Key 460 thus holds the crank 448 to theshaft 422 so the two components rotate as a single piece unit.

A hat 464 is disposed over shaft head 432. The hat 464, as seen in FIGS.36 and 37, has a cylindrical core 468. A brim extends outwardly radiallyoutwardly from and circumferentially around the core 468. The brim hasan inner section 469 that is the section of the brim that extendsradially outwardly from the core. Inner section 468 of the brim lies ina plane that is perpendicular to the top-to-bottom longitudinal axisthrough the core. Hat 464 is formed so this inner section of the brimextends outwardly from a location approximately midway along the lengththe core 468. The brim has an outer section 470 that extends upwardlyfrom the outer perimeter of the inner section. Hat 464 is formed so theinner diameter of the brim outer section 470 is slightly greater thanthe inner diameter of sleeve 127 integral with the shell top plate 122.

Hat 464 is formed to have a closed end bore 472 that extends upwardlyfrom the bottom of core 468. The core 468 is formed to define twodiametrically opposed notches 474. Notches 474 extend upwardly from thebottom of core 468. Each notch 474 opens into bore 472. Bore 472 isdimensioned to allow the shaft 432 to slip fit in the bore. The hat core468 is formed with a second bore, closed end bore 476. Bore 476 extendsdownwardly from the top of core 468. The hat is formed so that upwardlydirected portion of the brim inner section 469 is formed with a surface478 that is recessed relative to the outer portion of this section ofthe rim. This recessed surface 478 is understood to surround the core468. Above the brim hat 464 is formed to have two diametrically opposedopenings 477 that extend onto the core 468. Each opening 477 extendsinto bore 476.

Hat 464 is disposed over the head 432 of shaft 422 so head 432 isdisposed in and able to rotate in hat bore 472. The bottom face of thecore 468, which is the bottom of hat 464, seats on the step that is thetransition surface between shaft trunk 428 and head 432. A pin 480 isseated in bore 440 internal to the shaft head 432. The opposed ends ofpin 480 project radially outwardly from the shaft 422 so as to seat innotches 474 located at the base of hat 464. Owing to the presence of pin480 in the hat notches 474, the hat 464 is able to engage in a limiteddegree of rotation around the shaft 422. In some versions of theinvention, the components forming the assembly base are constructed sothat the hat can rotate between 5° and 45° around the shaft.

A pin 479, seen only in FIG. 34, extends downwardly from the brim innersection 469. Pin 479 is spaced radially outwardly from the core 468 ofhat 464. Not shown is the bore in the hat 464 in which the top of thepin 479 is press fit.

An arm coupler 486, also part of the cage driver 420, is disposed overhat 464. The arm coupler 486, seen best in FIGS. 38 and 39, includes acylindrical base 488. Arm coupler base 488 has an outer diameter thatallows the base to seat in the space immediately above the recessedsurface 478 of hat 464. A circular boss 490, also part of the armcoupler 486, rises above the top of base 488. Arm coupler 486 is formedso that the boss 490 has an outer diameter less than the outer diameterof the base 488. A bar 492, integral with the boss 490, rises above thetop surface of the boss. Bar 492 has opposed side surfaces that areparallel. The bar extends laterally across the boss to intersect the topto bottom common longitudinal axis of the base 488 and the boss 490.

The arm coupler 486 is further formed to have a closed end bore 494 thatextends upwardly from the bottom face of the base 488. The arm coupler486 is formed so that bore 494 has a diameter that allows the slipfitting of the hat core 468 in the bore. Arm coupler 486 is also formedto have two diametrically opposed openings 496 that extend inwardly fromthe outer surface of the base 488. Openings 496 are oval shaped and areformed in the arm coupler 486 to have major axes that are parallel tothe longitudinal axis through the coupler. The openings 496 each openinto bore 494.

When the cage driver 420 is assembled, the arm coupler 486 is seatedover hat core 468. A pin 502 is seated in at least one of the bores 477integral with the hat 464 so as to extend outwardly from the core 468 ofthe hat. The pin 502 extends into a one of the openings 496 internal tothe arm coupler 486. This pin-in-opening arrangement holds the coupler486 to that hat 464 so the coupler both will rotate in unison with thehat and is able to move longitudinally relative to the hat. A spring 504is seated in hat bore 476 and extends upwardly above the hat 464. Thespring 504 extends into the coupler bore 494 and presses against theinterior surface of the coupler 486 that defines the closed end of bore494. Spring 504 thus places a force on the arm coupler 486 that, in theabsence of an opposing force, holds the arm coupler in its dispositionrelative to hat 464.

A rocker arm 508, pivots the crank 448 to cause the like pivotal motionof the cage driver 420. The rocker arm 508, as best seen in FIG. 41, isgenerally in the shape of an elongated beam. In the illustrated versionof the invention, the arm has a first section 510 that is generallysolid. A slot 512 is formed in beam first section 510 to extend inwardlyfrom the outer end of the rocker arm 508. The opposed end of the armfirst section 510 is slightly larger in cross sectional width than therest of the section. Rocker arm has a second section 514 that extendsoutwardly from the first section 510. More particularly, the arm secondsection 514 extends outwardly from the end of the first section 510opposite the end in which slot 512 is formed. Rocker arm 508 is formedso the major axis through the arm second section 514 is angled relativeto the major axis through the arm first section 510. In the illustratedversion of the invention, rocker arm 508 is also shaped so the bottomface of the arm second section 514 is above the adjacent bottom face ofthe arm first section 510. The top face of the arm second section 514below the adjacent top face of the arm first section 510.

Two bores 516 and 518 extend top to bottom through the arm first section510. Bore 516 is located immediately inward of the free end of the armfirst section 510, the end of section 510 spaced from the second section514. Bore 516 intersects slot 512. Bore 518 extends through the end ofthe arm first section 510 that is adjacent the arm second section 514.The rocker arm 508 is further formed so that an elongated slot 520extends top to bottom through the arm second section 514.

A roller 524 is mounted in slot 512 internal to the rocker arm 508. Apin 522 the ends of which are seated in the sections of bore 516 oneither side of the slot 512 rotatably holds the roller 524 to the rockerarm 508. The components forming the assembly base 102 are arranged sothat the outer surface of the roller 524 projects beyond the perimeterof the rocker arm 508.

A pin 526, identified in FIG. 34, pivotally holds the rocker arm 508 tothe inner plate 150 immediately above the top surface of base 152 of theplate. The pin 526 is seated in one of the openings formed in the innerplate 150. When the rocker arm 508 is mounted to the inner plate 150,roller 524 is able to press against the outer faces of lobes 238 and 242of the arm cam 234.

When the rocker arm 508 is mounted to the inner plate 150, the armsecond section 514 is located between the tabs 454 integral with crank448. A pin 530 that extends through crank tabs 454 and arm slot 520couples the crank 448 to the rocker arm 508. In the depicted version ofthe invention, a block 528 is slidably disposed in the arm slot 520. Pin530 extends through a hole 529 formed in the block 528. Cage driver 420is further constructed so that pin 530 projects both above the toplocated crank tab 454 and the bottom located crank tab 454.

From FIGS. 33 and 34 it can be seen that the cage driver 420 includestwo torsion springs 532 and 534 that are disposed around shaft 422.Torsion spring 532 is disposed around the section of the shaft trunk 428below collar 430. Spring 532 is thus seated in void 156 formed in plate150. One leg of the torsion spring 532 is pressed against the section ofthe pin 530 that extends below the crank 448. The opposed leg of spring532 presses against a portion of the web 158 that defines void 156internal to inner plate 150.

The second spring, spring 534, is actually disposed around the sectionof the hat core 468 located below the brim 469. One end of spring 534 isdisposed against the section of pin 530 that extends above the crank448. The opposed leg of spring 534 presses against the pin 479 thatextends from hat 464. Spring 534 thus normally holds the hat 464 in afixed rotational orientation over shaft 422. The extent to which the hat464 is able to rotate is limited by the extent to which the hat notches474 can rotate over the pin 480 held fast to shaft 422.

During operation of the bone cleaner and bone mill of this invention,springs 532 and 534 can, individually or collectively, cause the rockerarm 508 to place an appreciable side loading force against arm cam 234.Balance collar 246 resists this force. The balance plate thus holds thearm cam 234 and by extension the tube cam 252 in axially stable positionwithin the assembly base.

A latch assembly 540, seen in FIGS. 5A, 42 and 43, is mounted to theunderside of the top plate 122 of the assembly base 102. The latchassembly 540 releasably holds first the cleaning module 602 and then themilling module 902 to the base 102. Latch assembly 540 includes twoprimary plates 542 and 544. Primary plates 542 and 544 are mounted tothe underside of the top plate 122 to pivot around a common axis. In theFigures the primary plates 542 and 544 are both seen being pivotallyheld to the undersurface of the top plate 122 by a common fastener 539.Fastener 539 defines the axis around which the primary plates 542 and544 pivot. Four secondary plates 546 are also pivotally mounted to theunderside of the top plate, three secondary plates identified in FIG.42. In FIG. 42 a single one of the fasteners 547 that holds one of thesecondary plates to the underside of the top plate 122 and around thesecondary plate pivots is identified. Each secondary plate 546 is formedwith a tab 548. The secondary plates 546 are mounted to the top plate122 so that each tab 548 extends out of a separate one of the openings118 in the top plate 122. Two of the secondary plates 546 are coupled toprimary plate 542 to move upon the pivoting movement of plate 542. Twoof the secondary plates 546 are coupled to the primary plate 544 to moveupon the pivoting movement of plate 544. In FIG. 5A, a single one of thepins 545 that connects one of the secondary plates 546 to primary plate542 for pivotal movement is identified.

Latch assembly 540 also includes two finger grips 562. The finger grips562 are located adjacent the curved outer side of the top plate 122closest to opening 126. A bracket 560 extends inwardly from each fingergrip 560. The brackets 560 extend through slot 119 formed in the rim 116so as to extend into the space immediately below the top plate. Eachbracket 560 connects the finger grip from which the bracket extends to aseparate one of the primary plates 542 or 544. One of the fasteners 563that holds the brackets 560 to each of the primary plates 542 and 544 isseen in FIG. 5A. Not identified are the openings in the primary plates542 and 544 and bracket 560 through which the fasteners 563 extend.

A spring 566 extends between the latch assembly primary plates 542 and544. Spring 566 is in compression to hold the primary plates in theposition in which the plate 542 and 544 are arcuately spaced from eachother. When the primary plates 542 and 544 are so spaced, the secondaryplates 546 are positioned so that tab 548 extend out of the openings 118integral with the shell op plate 122. The force spring 566 places on theprimary plates 542 and 544 can be overcome by the manual pressing of thefinger grips 562 towards each other. This displacement of the fingergrips 562 results in the like displacement of the primary plates 542 and544 so the plates 542 and 544 pivot inwardly towards each other. Theinward movement of the primary plates 542 and 544 results in thepivoting movement of plates 546 that retract tabs 546 inwardly away fromthe shell openings 118.

Two circuit boards 552 and 553 are also shown mounted to the undersideof top plate 122. Circuit board 552 is mounted to the top plate 122 soas to be adjacent the side edge of the plate closest to the shell facepanel 108. Circuit board 553 is mounted to the curved end of the platecloses to plate opening 124 to the top plate 122 so as to be adjacentthe side edge of the plate closest to the shell face panel 108.

Sensors 586 and 587, shown as block components in FIG. 44, are mountedto the circuit boards 552 and 553, respectively. Sensors 586 and 587each generate signals based on the absence/presence of a local magneticfield. In some versions of the invention, sensors 586 and 587 are Halleffect sensors. It should be understood that top plate 122 is formedfrom material that allows the transmission of localized magnetic fieldstherethrough. Specifically, the top plate 122 is formed from materialthat does not attenuate the passage of localized magnetic fields to theextent that the sensors 556 and 557 are not able to sense theabsence/presence of the fields.

From FIG. 44 it is further appreciated that sensors 586 and 587 are partof the sub-assembly that regulates the actuation of assembly 100 of thisinvention. This sub-assembly also includes a motor controller 596 alsodisposed in the assembly base. Motor controller 596 regulates theapplication of energization signals sourced from a power supply 595 tothe motor 140. The signals output by the sensors 586 and 587representative of the absence/presence of the localized magnetic fieldsare output to the motor controller 596.

Also part of the sub-assembly that regulates the operation of motor 140are two momentary contact switches 588 and 590. In FIG. 2, switches 588and 590 are called out as the control buttons disposed on the face panel108 of base shell 104. Switches 588 and 590 are shown connected to themotor controller 596.

The control sub-assembly is also shown as having two LEDs. LEDs 589, and591. LED 589 is shown as emitting light adjacent switch 588. LED 591 isshown emitting light adjacent switch 590. In some versions of theinvention each switch 588 and 590 is surrounded by a transparent ring,transparent rings not identified. The light emitted by each LED 589 and591 is visible through the transparent ring adjacent the switch 588 or590 with which the LED is associated.

In some versions of the invention one or both of the power supply 595and controller 596 are not disposed in the shell 104 of the base 102.For example in one version of the invention, the power supply 595 andmotor controller 596 are components of a control console to which thebase 102 is removably attached. One such control console is sold by theApplicant as the CORE Console. Features of this console are disclosed inU.S. Pat. No. 7,422,582/PCT Pub. No. WO 2006/039331, the contents ofwhich are explicitly incorporated by reference. Not shown is the cablethat is used to connect the components internal to the control consoleto the components internal to the assembly base 102.

III. Cleaning Module

The cleaning module 602 of assembly 100 of this invention, as seen45-48, includes a base 604 to which a shell 660 is removably attached.Base 604 and shell 660 collectively form substantial portions of thehousing of the cleaning module 602. A fluted screw 690 is rotatablymounted to the base 604 and disposed in the shell 660. A shaving tube724 surrounds the fluted screw 690. In the illustrated version of theinvention, the shaving tube 724 is mounted to a plate 710 that rests onthe upwardly directed surface of the base 604. Plate 710 and shavingtube 724 are fitted to the cleaning module to be able to rotate over thebase 604. Within the module housing, a cage 764 surrounds the flutedscrew and shaving tube 724. Cage 764 is located at the free end of anarm 750. Arm 750 has features that facilitate the coupling of the arm tothe arm coupler 436 of assembly base 102.

A cap 680 is disposed over shell 660. The cap 680 is part of the housingof the cleaning module 602. Cap 680 defines a catch space 682 above theshell 660. Catch space 682 is the space internal to the module housingthat receives the soft tissue cleaned from the bone stock. A hub 850 isdisposed in the catch space 682. Hub 850 steadies the fluted screw 680and the shaving tube 724.

The cleaning module base 604, as seen in FIGS. 49 and 50, is a singlepiece component. The base 604 includes a planar plate 606. Plate 606 hasa shape that approximates the shape of the assembly base top plate 122.An inner rim 608 extends downwardly from the outer perimeter of baseplate 606. An outer rim 610 extends downwardly and outwardly around theinner rim 608. Base 604 is formed so that when cleaning module 602 isseated on the assembly base 102, outer rim 610 integral with module 602seats against rim 116 integral with the assembly base 102.

Cleaning module base 604 is further formed so four slots 612 extendthrough the base outer rim 610, two slots identified. Slots 612 arepositioned and shaped so that when the cleaning module 602 is seated onthe assembly base 102, each tab 546 integral with the assembly baselatch assembly 540 is in registration with and can seat in a separateone of the slots. The base 604 is further formed so a slot 614 extendsthrough the inner rim 608. The slot 614 extends through a portion of oneof the curved end sections of the rim 608. Slot 614 extends a shortdistance into plate 606. Base 604 is also formed with a notch 615 thatforms a void in plate 606. Notch 615 extends inwardly from a portion ofthe plate 606 opposite slot 614.

Module base 604 is further formed to have two openings 622 and 630.Opening 622 is positioned so that when the module 602 is seated on theassembly base 102, the opening is disposed over the primary coupler 194and the tube coupler 348. The base 604 is further formed so on the topsurface of plate 606 a circularly shaped recessed surface 623 iscentered around and extends circumferentially around opening 622. Themodule base 604 is formed to have an outer ring 624 that extendsdownwardly from the underside of plate 606 around opening 622. An innerring 626 extends downwardly from the downwardly directed face of theouter ring 624. Outer ring 624 and inner ring 626 have the samediameter, the diameter of opening 622. Inner ring 626 has an outerdiameter less than the outer diameter of the outer ring 624. The modulebase 604 is further formed so that when the module 602 is seated on theassembly base 102, the exposed circular face of the inner ring isdisposed against the surface of top plate 122 around opening 124. Base604 is further formed to have a number of bores 628, one boreidentified, that extend inwardly from the circular face of the outerring 624 that is located immediately radially outwardly of the outerring 622.

The opening 630 formed in plate 606 so that when the module 602 isseated on the assembly base, the opening 630 is in registration with theopening 126 formed in top plate 122. Base 604 is further formed so as tohave an island 631 that extends a short distance above the top surfaceof plate 606. The base 604 is shaped so that island 631 surroundsopening 630.

The module base 604 is further formed so that two lock stops 632 and 638project downwardly from the undersurface of plate 606. Stops 632 and 638are located a common radial distance away from the center of opening622. Stops 632 and 638 are arcuately spaced apart from each other byapproximately 90°. A small rib protrudes downwardly from theundersurface of the plate 606 adjacent each stop 632 and 636. Rib 634 islocated adjacent stop 632. Rib 636 is located adjacent stop 638. Theribs 634 and 638 lie on the same circle around opening 622 around whichthe stops 632 and 636 are located. Ribs 634 and 636 do not extenddownwardly from the undersurface of the plate 606 to the same extentstops 632 and 638 extend downwardly. Base 604 is further formed so thatin planes perpendicular to the longitudinal axes along the ribs 634 and636, the ribs have a convex shape.

The module shell 650, seen best in FIGS. 47 and 48, is formed to have anouter wall 652. Outer wall 652 is shaped to sit on the outer stepbetween the inner and outer rims 608 and 610, respectively of base 604.The outer wall 652 is further shaped to extend around the base so as toextend around approximately 70% of the circumference of the base. Moreparticularly, outer wall 652 does not subtend the curved end of the baseclosest to opening 622. Where the outer wall 652 does not subtend thestep surface of the module base 604, shell 650 is shaped to have aninner wall 656. The shell 650 is shaped so the inner wall 656 is locatedradially inwardly from the outer wall 652. Shell 650 is further formedso adjacent the top of inner wall 656 there is an inwardly extendinggroove 655. Groove 655 extends along to the right to left length of wall656. End panels 654 extend inwardly from the opposed ends of the outerwall 652 to the adjacent ends of the outer wall 656. The shell 650 isfurther formed so that the inner wall 656 does not extend the fulllength of the outer wall 652. While the tops of the walls 652 and 656are generally in the same plane, the inner wall 656 only extendsapproximately one-third the distance downwardly that the inner wall 652extends downwardly.

Shell 650 also has two tabs 653, one tab identified in FIG. 48. Tabs 653extend inwardly from the bottom of the outer wall 652. The tabs 653 arelocated adjacent the opposed ends of the wall 652. When shell 650 isseated on base 604, one tab 653 is located below slot 614. The opposedtab 653 is located below notch 615.

Three webs 658, 660 and 666 extend between the opposed ends of the outerwall 652. Web 658 is generally vertically aligned and is locatedoutwardly of the inner wall 656. The web 658 curves from one of the endpanels 654 to the opposed end panel 654. The bottom edge of web 658 islocated above the bottom edge of the outer wall 652. The top edge of web658 is located below the top edge of the inner wall 656.

Web 660 extends upwardly and inwardly from the top of web 658. Web 666extends inwardly and upwardly from web 660. The shell 650 is formed sothe outer perimeter of web 666, the portion of web 666 closest to web660 is stepped below the inner perimeter of web 660. Web 666 extend tothe bottom of the inner wall 656. Webs 658, 660 and 666 are arcuate andsubtend the gap between the ends of the outer wall 652. Shell 650 isfurther formed so that two ribs 661 and 662 protrude upwardly and extendthe width of web 660. Rib 661 is located a short distance away from afirst one of the shell end panel 654. Rib 662 is located a shortdistance with from the opposed shell end panel 654. Ribs 661 and 662each extend from the outer perimeter of web 660 to the inner perimeterof the web 660.

The cleaning module shell 650 includes a lid 670. The lid 670 is locatedabove the shell outer wall 652 and inner wall 654. An opening 672 isformed in the lid 670. A boss 676 extends downwardly from theundersurface of lid 670. The shell 650 is formed so that when the shellis disposed on the module base 604, the shell opening 672 is centeredover base opening 622 and boss 676 is centered over base opening 630.Three bosses 673, one boss identified extend upwardly from the topsurface of lid 679. Bosses 673 are centered around the center of shellopening 672 and are spaced radially away from the outer perimeter of theopening. Bosses 673 are equangularly spaced apart from each other.

Cap 680 also forms part of the housing of the cleaning module 602. Thecap 680 is disposed over the lid 670. The means by which the cap 680 issecured to the lid 670 is not part of the invention. The lid 670 thusforms the base of the catch space 682 defined by the cap 680. Opening672 in the lid 670 opens into the catch space 682.

A ring 681 formed of elastomeric material extends around the top of cap680. The ring 682 is provided to facilitate the grasping of theintegrated shell 650 and cap 680 unit.

The fluted screw 690, seen in FIG. 51, is rotatably mounted to baseplate 606. The screw 690 includes a cylindrical stem 692. At a locationstarting approximately one-fifth the way up from the bottom of the stem,flutes 694, one flute identified, extend helically around the stem 692.The flutes 694 extend to the top of the stem 692. Each flute 694 isformed to define a cutting edge 696, one cutting edge identified.Extending upwardly from the base of stem 692, screw 690 is formed tohave closed end bore 698 seen in FIG. 51. Bore 698 is dimensioned toreceive pin 198 integral with the primary coupler 194. Fluted screw 690is further formed to have three equangularly spaced apart notches 702that extend upwardly from the base of the stem 692, one notchidentified. Each notch 702 extends from the outer perimeter of the stem692 to the bore 698. The notches 702 do not extend as far up the stem692 as bore 698. The notches 702 have a common width. Each notch 702 issufficiently wide so a tooth 202 integral with the primary coupler 194can seat in the notch. The fluted screw 690 is further formed so aclosed end bore 704, seen in FIG. 46, extends downwardly from the top ofstem 692. Bores 698 and 704 are coaxial with the longitudinal axisthrough stem 692.

Rotating plate 710, sometimes identified as the tumble plate 710, seenin FIGS. 46 and 51, is seated on the module plate 606. The top surfaceof the tumble plate 710 is essentially planar in shape. A boss 712extends downwardly from the undersurface of the tumble plate 710. Boss712 has a diameter that allows the boss to seat and rotate in opening622 formed in the module base 604. A bore 714 extends upwardly from thebottom of boss 712 through the boss and to the top surface of the plate710. At the bottom end of the boss 712 a counterbore 716 extendsradially outwardly around bore 714. Counterbore 716 has a diameter thatis approximately 2 mm less than the diameter of the tube coupler 348.Plate 710 is further formed to have three equangularly spaced apartnotches 718. Notches 718 extend radially outwardly from the outerperimeter of counterbore 716. Each notch 718 is able to receive aseparate one of teeth 353 integral with the tube coupler 348.

A ring 720 also protrudes downwardly from the undersurface of plate 710.Ring 720 is coaxial with and spaced radially outwardly from boss 712.The outer diameter of ring 720 is marginally less than the diameter ofthe outer perimeter of the recessed surface 623 that surrounds opening622 internal to module base 604. When cleaning module 602 is assembled,the plate 710 seats on plate 606 so boss 712 is able to rotate inopening 622. The ring 720 is located immediately inside of the step thatdefines the transition from recessed surface 623 and the surroundingportion of the plate 604. Ring 720 thus minimizes lateral wobble of thetumble plate 710 in the cleaning module 602.

Shaving tube 724, seen best in FIG. 46, extends upwardly from the bore714 internal to plate 710. The tube 724 is further shaped to have awindow 728. Window 728 extends into the lumen that extends axiallythrough the tube and are diametrically opposed to each other around thelongitudinal axis through the tube 724. Window 728 is defined by twoarcuately spaced apart and longitudinally extending cutting edges 726formed in the tube 724, one cutting edge identified. Each cutting edge726 is the edge defined by the intersection of the inner wall of thetube and a side surface that extends inwardly from the outer wall of thetube to define a side perimeter of the associated window 728.Collectively the components forming the cleaning module 602 are shapedso that there is a clearance between the edges 696 of the screw flutes694 and the cutting edges 726 formed in tube 724 of between 0.03 and 0.5mm.

The shaving tube 724 is press fit mounted in bore 714 internal to tumbleplate 710. Shaving tube 724 is mounted to the plate 710 so that bottomend of window 728 is essentially flush with the top surface of theplate.

Arm 750 and cage 764, best seen in FIGS. 52-55, are formed as a singlepiece unit. Arm 750 is in the form of an elongated bar. One end of thearm 750 is rounded. Molded into the top of arm 750 are cavities 752. Thecavities 752 are used as standard guides to provide visualrepresentations of the maximum dimensions of the bone stock that can becleaned by the module 602.

The arm 750 is formed so that inward of the rounded end of the arm,there are first and second bores 754 and 756 which are accessible fromthe bottom of the arm. Bore 754 is circular in shape and extendsupwardly from the under surface of the arm 750. Bore 754 opens into bore756. Bore 756 is, in cross sectional planes parallel to the longitudinalaxis through the bore 756, generally in the shape of a rounded triangle.Bore 756, in cross section, subtends an area less than the crosssectional are of bore 754. Not identified is the step in the arm betweenbore 754 and bore 756. Bore 756 is close ended. A closed end cylindricalbore 757, seen in phantom only in FIG. 53, extends upwardly from the topof the closed end of bore 756.

The arm 750 is further formed so as to have a dimple 758, identified inFIG. 54, that extends inwardly from the top surface of the arm. Dimple758 is concave in shape. The dimple 758 is formed in the arm to beconcentric with bore 754. Arm 750 is formed so that when the shell 650is fitted over the base 604, the shell boss 676 is seats in the dimple758. A void 759 is seen extending upwardly from the undersurface of thearm 750. Void 759 is separate from bores 754 and 756. The void 759 ispresent for manufacturing reasons only.

The cage 764 is a structure generally formed as a triangle with roundedvertices. The cage 764 extends outwardly from the end of the arm 750opposite the curved end of the arm. Arm 750 and cage 764 are formed sothat a relatively short length panel 766 of the cage 764 extends along aline that is approximately parallel to the longitudinal axis of the arm.A medium length panel 768 of the cage extends generally perpendicularlyfrom the short length panel and is adjacent the arm 750. The longestlength panel 770 of the cage, essentially that panel that is thehypotenuse of the triangle formed by the cage, extends between the freeends of panels 766 and 768. Cage panel 770 is spaced away from arm 750.

Cage 764 is formed to have structural features that extend inwardly fromthe surfaces of the panels 766-770 into the void space 765 internal tothe cage. One of these structural is an indentation 769 in panel 770.

Indentation 769 is located adjacent the curved vertex between panels 768and 770. Indentation 769 appears to extend into void space 765.

A second structural feature that extends into void space 765 is a pressblock 772. The press block 772 consists of portions of the panel 768 andthe portion of the adjacent curved vertex that forms the section of thecage between panel 768 and panel 770. The press block 772 has a facethat is located inwardly of the inner surfaces of panel 768 and theadjacent curved vertex. The cage 764 is formed so the press block 772extends upwardly from the bottom edge of the panel. The press block 772extends approximately half the distance up the top-to-bottom distance ofthe cage. The press block 772 presents a curved face to the void spacedefined by the cage. More particularly, the press block 772 is curved sothat the face has a curvature that, in planes perpendicular to thebottom-to-top longitudinal axis along the press block, is concave.

A third structural feature of the cage 764 that projects into void space765 is a rib 776 that extends inwardly from the inner surface of panel768. Rib 776 has a shape that, in planes perpendicular to a bottom-totop axis along the panel 766, is triangular. The apex line along the rib776 is the portion of the rib spaced furthest from panel 766. Rib 776does not have a longitudinal axis that simply extends perpendicularlyupward from the bottom of the panel 768. Instead, at the bottom of thepanel, the base of rib 776 is located within an area subtended by thearm 750. Extending upwardly from this portion of panel 768, the rib 776extends diagonally towards the curved vertex between cage panels 768 and770. Thus, the top portion of rib 776 is integral with a section of thepanel 768 that is spaced away from the arm 750.

A rib 780 is the fourth structural member of the cage 764 that extendsinto void 765. Rib 780 extends inwardly from the inner surface of panel766 and the curved vertex between panel 766 and panel 770. In planesthat extend vertically, top to bottom along the cage 764, rib 780 has across sectional shape that is generally triangular. Cage 764 is furtherformed so that the apex of rib 780 extends along a line that is notparallel to the bottom of the cage. Instead, the cage is formed so thatthe end of the rib 780 that extends outwardly from panel 766 projectsoutwardly from a location generally near the mid-section between the topand bottom of the panel 766. As the rib extends away from panel 768 andcurves around vertex that leads to panel 770, the rib extends upwardly.The second end of the rib 780 thus terminates at the top edge of thecage where the vertex between panels 768 and 770 curves into panel 770.Rib 780 has a surface 782 below the apex of the rib. Surface 782 tapersupwardly from both panel 766 and vertex between panels 766 and 770.Starting where vertex 771 curves away from panel 770, surface 782 curvesaround and downwardly along around the vertex. From the vertex, as thesurface 782 extends along panel 766, surface 782 extends downwardly.

A web 790 extends between the outside of arm 750 and the outer surfaceof cage panel 768 that projects away from the arm. A tab 792 extendsoutwardly from the top of the cage 764. More particularly, the tab 792projects outwardly from the top of vertex 769. Tab 792 is formed with anarrow head shaped icon 794 that points away from the cage 764

A drive pin 802, best seen in FIGS. 56 and 57, is mounted to and extendsoutwardly from arm 750. The drive pin 802 includes a cylindrical stem804. Stem 804 is dimensioned to seat in bore 754 formed in the arm 750.Stem 804 has a diameter approximately equal to the diameter of head 490of arm coupler 486 that is part of the assembly base 102. A head 806extends upwardly from the stem 804 of pin 802. Head 806 is triangular inshape and subtends a cross sectional area that is within the circledefined by stem 804. The pin head 806 is dimensioned to tightly fit inthe bore 756 formed in the arm 750.

The drive pin 802 is further formed so that at the base of stem 804, theend of the stem opposite the end from which head 806 extends, two toes808 extend away from the stem. Toes 808 lie in a common plane. The toes808 are arcuately spaced apart from each other. Drive pin 802 is shapedso that each toe 808 has an outer side surface that essentially extendstangentially away from the curved wall that forms that outer surface ofpin stem 804.

Drive pin 802 is further formed so as to have a slot 810 that extendsupwardly from the base of stem 810. The slot 810 is rectangular in shapeand is dimensioned to receive the bar 492 integral with the assemblybase arm coupler 586. In the illustrated version of the invention, slot810 projects slightly radially beyond the stem 810 into a web betweentoes 808. A bore 812 extends upwardly from the inner surface of stem 804that defines the ceiling of slot 810. Bore 812 extends through the stem804 and head 806.

Upon assembly of the cleaning module 602, the arm 750 is positioned sothe bores 754 and 756 are located over opening 630 in the module base604. As a result of the positioning of the arm 750, the cage 770 isdisposed over plate 710 to surround the fluted screw 690 and thesurrounding tube 724. The drive pin stem 804 is inserted in opening 630so the stem and head seat in, respectively, bores 754 and 756 formed inthe arm. A fastener 814, seen only in FIG. 46, that extends through pinbore 812 and bore 757 internal to arm 750 holds pin 802 to the arm 750.The toes 808 and slot 810 integral with the drive pin are locatedadjacent the undersurface of plate 604, the surface of the plateopposite the surface against which arm 750 rests.

A lock disc 818, now described by reference to FIGS. 60 and 61, isrotatingly mounted to the module base 604 so as to be located below theundersurface of plate 604. Lock disc includes a circular plate 820. Twotabs 822 are disposed on the top surface of the plate 820. The tabs 822are diametrically opposed to each other relative to the center of theplate. Each tab 822 extends upwardly from the top surface of the plate820. The portion of the tab 822 that is disposed above the plate topsurface projects radially outwardly beyond the perimeter of the plate820. A ridge 824 also extends upwardly from the top surface of plate820. Ridge 824 is a three section structure, individual sections notidentified. There is a center section located adjacent the perimeter ofthe plate 820. This center section is curved in shape and subtends anarc of approximately 20 to 30°. Two end sections project radiallyoutwardly from the opposed ends of the middle section. The end sectionsproject a short distance, approximately 5 mm, beyond the perimeter ofthe plate. Ridge 824 thus defines a mortise 826 located adjacent theouter perimeter of the plate 820.

The lock disc 818 is further formed to have a center located throughhole 826. The lock disc 818 is formed so that hole 826 has a diameterthat the outer ring 624 of the module base 604 can seat in the hole andthe disc 818 can rotate around the ring 624. An atoll 828 formedintegrally with plate 820 extends upwardly from top surface of the plateand extends around hole 826. The atoll 828 is formed to have outer sidesurfaces that are located different distances from the center of hole826. A first side surface, surface 829 the edge of which is identified,is an arcuate surface that is located furthest from the center of hole826. The atoll is formed so that surface 829 subtends an arc thatextends more than 180° around the perimeter of the atoll 828. At oneend, surface 829 curves into a surface 830. Surface 830 goes along apath around hole 826 that is generally linear in shape. Surface 830merges into an arcuate surface, surface 832. Surface 832 is centeredaround center the center of hole 826. Relative to surface 829, surface832 is located closer to hole 826. A linear surface, surface 834,extends both arcuately and radially outwardly away from surface 832.Surface 834 extends to an adjacent linear surface, surface 836. Surface836 is located along a line that is approximately parallel to thetangent line that would be present on surface 832, where surfaces 832and 834 meet. Surface 838 extends to surface 829.

The lock ring 818 is further formed so that a tab 839 extends radiallyoutwardly from the surface 828 of the atoll 828. Tab 839 is formed withan indentation 840. The indentation 840 is dimensioned to receive eitherone of the ribs 634 or 636 that extend downwardly from the module base604.

A ring 842 extends downwardly from the undersurface of the lock disc818. Ring 842 extends circumferentially around hole 826. A rim 844 alsoextends downwardly from the undersurface of the plate 824. The rim 844extends downwardly from the outer perimeter of the disc 818. The rim 844does not extend completely circumferentially around the outer perimeterof the plate 824. The plate has a section that subtends an arc ofbetween approximately 30 and 50° that is rim free. One end of the rim844 is formed to have a ramp surface, surface 846. As surface 846extends arcuately, the surface tapers away from the surface of the plate824 towards bottommost surface of the rim 844.

Lock ring 818 is further formed to have a closed end bore 847 thatextends upwardly from bottom directed face of ring 842. Bore 847 islocated in the portion of the ring above ridge 824. A magnet 848 isdisposed in bore 847.

Cleaning module 602 is assembled by positioning the lock disc 818adjacent the underside of the base 604 so outer ring 624 seats in hole826 and extends downwardly a short distance beyond the disc. As a resultof this positioning of the lock disc. Toes 808 integral with the drivepin 802 are disposed on the surface of the disc adjacent the atoll 828.A retaining ring 849 is seated against the stepped surface between therings 624 and 626 integral with the module base 604. Fasteners 851, oneidentified in FIG. 72, extend through holes in the ring 849 and bores628 in the base to hold the ring to the base. Ring 849 has an outerdiameter greater than the diameter of the hole 826 internal to the lockdisc 818. The ring 846 thus projects under the ring 842 integral withthe module base 604. Ring 849 thus holds the lock disc to the modulebase 604. When the cleaning module is assembled, the lock disc 818 isspaced below the undersurface of plate 606. Tabs 822 and mortise 826 aredisposed in the space between plate 606 and disc 818. The mortise 826 isaccessible through slot 614 in ring 608 integral with the module base604.

A hub 860, seen best in FIGS. 58 and 59, is disposed in catch space 682internal to the cleaning module 602. Hub 860 is a single piececomponent. The hub 860 has a disc shaped base 862. Base 862 is formedwith a center opening 864 that extends between the opposed downwardlyand upwardly directed surfaces of the base. The downwardly directedsurface of base 862 is understood to be the surface that is faces theunderlying shell lid 670. Three bores 868, one bore identified, that arespaced radially outwardly of opening 864 and equangularly spaced apartfrom each also extend between the opposed downwardly and upwardlydirected surfaces of base 862. Each bore 868 has a counterbore,(counterbores not identified). Hub 860 is shaped so that when the base862 is positioned so that the hub center opening 864 is disposed overthe opening 672 in the shell lid 670, each one of the bosses 673 formedin the lid 670 seats in separate one of the counterbores associated withbores 868. Fasteners that extend through the lid bosses and the hubbores 868 hold the hub to the top of the shell lid 670, fasteners notillustrated.

Three equangularly spaced apart stanchions 870, two stanchionsidentified, also part of the hub 860, extend upwardly from the outersurface of the base 862. The stanchions 870 are located on a circlelocated adjacent the perimeter of the center opening 864. A web 872extends radially inwardly from the top of each stanchion 870. Webs 872meet at a location above the center of center opening 864. A pin 874extends downwardly from the location where webs 872 meet. A foot 878extends below the free end of the pin 878. Foot 878 has a diameter lessthan the diameter of the pin 874. More particularly, the pin foot 878has a diameter that allows the pin foot 878 to closely slip fit in bore704 formed in the fluted screw. When the cleaning module 602 isassembled, the pin foot 878 seats in fluted screw 690 and the screw isable to rotate around the pin 874.

A latch 880, see best in FIGS. 47 and 48, is moveably mounted to theshell 650. The latch 880 is formed with a number of panels such that thepanels forming the latch are located adjacent the shell inner wall 656and adjacent webs 658, 660 and 666. Two arcuately shaped beams 882extend downwardly from one of the panels. An arcuate shaped lip 884projects outwardly from the top most webs. The components forming thecleaning module 602 are formed so that the latch 880 can be snap fittedto the shell such that beams 882 seat over shell web 666 and lip 884seats in shell groove 655. The latch 880 subtends an arc less than thearc subtended by the shell inner wall 656 and adjacent webs 658, 660 and666. The latch 880 can thus slide over the shell inner wall 656 andadjacent webs 658, 660 and 666.

The bottommost panel of the latch 880 extends below shell web 658. A tab886 projects perpendicularly away from the bottom edge of the bottommostpanel of the latch. Tab 886 thus extends below and inwardly from thebottom edge of shell web 658. The latch is shaped so that the tab 886can seat in the mortise 826 defined in lock disc 818.

IV. Milling Module

The milling module 902 as seen in FIG. 62, includes a bottom shell 904and a top shell 940 that collectively form the housing of the module.Top shell 940 is disposed above the bottom shell 902. A cutting disc 958and an impingement plate 984 are disposed between the shells 902 and940. A hopper 952 extends upwardly from the top shell 940. A plunger 953can be pushed through the hopper 952. A catch tray 980 is removablyattached to the bottom shell 904 below the cutting disc 958.

As seen in FIGS. 63 and 64, bottom shell 904 integral with the cleaningmodule has a rim 906. The rim 906 is dimensioned to seat on the step 115that extends around the top of the assembly base 102. Rim 906 is formedto have four openings 908, one opening identified. Shell 904 is formedso that when the milling module 902 is seated on the assembly base 102,latch assembly tabs 548 can seat in openings 908 to releasably hold themodule 902 to the base 102.

The bottom shell 904 is further formed to have a planar top surface 910.A recessed surface 912 that is generally circular in shape is locatedbelow the top surface 910. Plural bores 913, one bore identified, extendinwardly from the top surface 910. Bores 913 are located around andspaced radially outwardly from the recessed surface 912. Shell 904 isformed so that there are two openings in the recessed surface 912. Afirst opening, opening 914, is circular in shape and is concentric withthe center of the recessed surface 912. The outlet opening, opening 918,extends inwardly from the outer perimeter of the recessed surface 912.Opening 918 extends toward opening 914. A ring 916 extends upwardly fromthe recessed surface 912 and circumferentially surrounds opening 914.Ring 916 functions as a barrier between opening 914 and opening 918.Shell 904 has a second ring, ring 920, that also extends upwardly fromrecessed surface 912. Ring 920 is located immediately inward of theouter perimeter of the recessed surface 912. Ring 920 does not extendcircumferentially around recessed surface 912. Instead, opening 918interrupts ring 920.

Bottom shell 904 is further formed to have a number of panels thatextend upwardly from the rim 906 to the top surface 910, (panels notidentified). One of the side panels is formed with an opening 924.Opening 924 extends inwardly into the shell and is positioned to belocated below and contiguous with opening 918. The bottom shell 904 isalso shaped so that the panel of the shell that forms top surface 910 isshaped to have a notch 911. Notch 911 extends inwardly from the portionof the top surface-defining panel that defines opening 924

A sleeve 926 extends downwardly from the underside of the shell recessedsurface 912. Sleeve 926 defines a through bore 928 that extendsdownwardly from opening 914. The bottom shell 904 is further formed so anumber of webs 930 extend downwardly from the undersurface of the topsurface and inwardly from panels that form the side of the shell. Webs930 provide structural shape to the bottom shell. One of the webs 930defines an upwardly extending opening 932. The bottom shell 904 isshaped so that when the milling module 902 is placed on the assemblybase 102, bore 928 is centered over the primary coupler 194 and opening932 is centered of the arm coupler 486.

The top shell 940, now described by reference to FIGS. 65 and 66,integral with milling module 902 has a planar shaped base 942. The shellbase 942 is dimensioned to seat over the top surface 910 of the bottomshell 904. Top shell 940 is formed to have a circularly shaped raisedsurface 944 that is located above the planar bottom face of the base942. A set of openings 943, extend top to bottom through the portion ofshell 940 that defines the base 942. Openings 943 are located around andradially outwardly from the raised surface 944. Milling module 902 isformed so the raised surface 944 is positioned to be concentric with andhave the same diameter as the recessed surface integral with the bottomshell recessed surface 912. Each opening 943 is centered above a bottomshell bore 913. Fasteners 941, one seen in FIG. 65, extend through eachtop shell opening 943 into the underlying bottom shell bore 913. Thefasteners 941 thus hold the top shell 940 to the bottom shell 904.

Two rings that are concentric with the raised surface 944 extenddownwardly from base 942. An inner ring 945 extends downwardly fromsurface 942 adjacent the center of the surface. An outer ring 946extends downwardly from the raised surface and is located slightlyinward of the outer perimeter of the raised surface. More particularly,when the milling module 902 is assembled, ring 945 is disposed over thering 916 integral with the bottom shell 904. The outer ring 946 isdisposed over the underlying ring 920.

The shell base 942 is further formed to have a notch 943. Notch 943 isoval in shape. The notch 943 is positioned so that, upon assembly ofmodule 902, the notch is located immediately above the notch 911 formedin the top surface 910 of the bottom shell. Notch 943 does not extendcompletely through the base 942.

Base 942 of the top shell 940 is further formed to have an inlet opening948. Inlet opening 948 opens into a section of raised surface 944between rings 944 and 946. More particularly, the top shell opening 948is positioned to be in registration over the bottom shell opening 918.Top shell 940 is further formed so that the hopper 952 extends upwardlyfrom the shell base 942 around inlet opening 948. The base 942 of topshell 940 is also formed to have a cavity 950, the edge of which isidentified in FIG. 66. Cavity 950 extends upwardly from the raisedsurface 944. The top shell 940 is formed so that cavity 950 is adjacentand contiguous with inlet opening 948.

Cutting disc 958, seen best in FIG. 67, is circular in shape and isdimensioned to sit in the space between the bottom shell recessedsurface 912 and the top shell raised surface 944. More particularly, thecutting disc 958 rests on the rings 916 and 920 that extend above therecessed surface 912. The cutting disc has a diameter approximately 4 mmless than the diameter of the void space in which the disc is seated.The cutting disc 958 has a thickness approximately 0.25 mm less than thedistance separating the bottom shell rings 916 and 920 from the topshell rings 945 and 946. The cutting disc 958 is thus capable ofrotating in the void space in which the disc is seated as well as alimited amount of side to side movement and a limited amount of up anddown movement.

The cutting disc 958 is formed with plural cutting elements 960, oneelement identified. The exact structure of the cutting elements 960 arenot part of the current invention. One such structure of cuttingelements is disclosed in the incorporated by reference U.S. Pat. Pub.No. US 2009/0118735/PCT Pub. No. 2009/061728. Generally, it should beunderstood each cutting element has a shearing edge 962, (one edgeidentified). Each shearing edge 962 defines a portion of an opening 963in the cutting disc 958, one opening identified. The cutting disc isfurther formed to have four equangularly spaced apart openings 964 (oneopening identified). The openings 964 are located radially inward of thecutting elements 960.

A shaft 966, seen best in FIGS. 68 and 69, extends downwardly from thecenter of the cutting disc 958. The shaft 966 is generally cylindricalin shape. The shaft is formed to have a head 970. The shaft head 970 hasa diameter that allows the head to seat in and rotate in bore 928internal to the bottom shell 904. A cylindrical stem 972 extends belowthe head 970. Stem 972 has a diameter less than that of the head 970.The shaft is formed so a closed end bore 974 extends upwardly from thebottom of the stem 972. The bore 974 is centered on the longitudinalaxis of the shaft 966. Bore 974 is dimensioned to receive the pin 198integral with primary coupler 194. The shaft 966 is further formed so asto have three equangularly spaced apart notches 976 that extend radiallyoutwardly from the base of bore 972. The notches 976 do not extend asfar upwardly into the shaft stem 972 as bore 974. Notches 976 aredimensioned to receive the teeth 202 integral with the primary coupler194.

Four pins 980, one pin identified, extend upwardly from the top surfaceof shaft head 970. Pins 980 extend through and over the opening 964internal to the cutting disc 958. The pins 980 thus hold the shaft 966to the cutting disc 958. When the milling module 902 is assembled, shaft966 is disposed in bore 928 internal to the bottom shell 904.

An impingement plate 984, seen in FIG. 62, is mounted in cavity 950formed in the top shell 940. The impingement plate 984 is formed to havea surface that is immediately below inlet opening 948. Milling module902 is designed so that when the module is actuated, the shearing edges962 of the cutting disc rotate towards the over surface of theimpingement plate 984.

The catch tray 988, now described by reference to FIGS. 70 and 71, isdimensioned to slidably seat in opening 924 internal to the bottom shell904. The catch tray 988 has a base 990 from which a set of panels 992extend upwardly, three panels identified. A lip 994 extends upwardlyfrom the innermost panel 992, the panel located closest to the shellsleeve 926. Catch tray 988 is formed so that when the tray is removedfrom the rest of the milling module 902, the lip sweeps under thesection of the cutting disc 958 located immediately above opening 918.

A handle 996 also projects outwardly from the outermost panel 992, thepanel spaced furthest from the panel from which the lip 994 extends.Handle 996 extends in front of the panel with which the lip isassociated. Handle 996 functions as the portion of the catch tray theuser grasps to insert the tray in and remove the tray from the rest ofthe milling module 902.

A latch 998 is pivotally mounted to handle 996. Latch 998 includes a tab1002 that projects above the rest of the catch tray 988. Tab 1002 ispositioned so that when the catch tray is full seated in opening 924,the tab is seated in the notch 943 internal to the top shell 940.Springs 1004, one spring identified, place a force on the latch thatnormally holds the latch in the locked state, the state in which tab1002 is disposed in notch 943. Finger force on the body of latch 998 issufficient to overcome the force imposed by the springs 1004 so as topivot the latch 998. The pivoting of the latch 998 rotates tab 1002 outof the notch 943. Once the tab 1002 is so rotated, the catch tray 988can be removed from the rest of the milling module 902.

A magnet 1010 is mounted in the base 990 of the catch tray 988. Notidentified is the bore in the base 990 in which the magnet 1010 isseated. The components forming assembly 100 of this invention arearranged so that when the catch tray 988 is latched in the millingmodule 902 and the cleaning module is seated on the assembly base 102,magnet 1010 is located above sensor 587.

V. Operation

A first step in preparing assembly 100 of this invention for use is theconnection of the console containing the power supply 595 and/or motorcontroller 596 to the assembly base 102. This step is required if thesesub-assemblies are separate from the assembly base 102. The cleaningmodule 602 is then seated over the top plate 122 of the assembly base.More particularly, the cleaning module 602 is fitted to the assemblybase so that tabs 548 that are part of the latch assembly 540 extendthrough the slots 612 in the cleaning module. Spring 566 exertssufficient force on latch plates 542 and 544 and, by extension, latchplates 546, to maintain tabs 548 in their outwardly directed positions.When the tabs 548 are in the outwardly directed position, latch assembly540 is in the latched state.

When the cleaning module 602 is latched to the assembly base 102, stem692 of fluted screw 690 is disposed over the primary coupler 194 as seenin FIG. 72. If the coupler teeth 202 are not seated in overlying flutenotches 702, the coupler 194 bears down against spring 212. The notch718-defining portion of the boss 712 integral with plate 710 is disposedover the tube coupler 348. If teeth 353 integral with the tube coupler348 are not seated in notches 718, the tube coupler 348 pushes downagainst spring 394. Stem 804 of drive pin 802 is disposed over cagecoupler 486. If the bar 492 integral with the arm coupler 486 is notseated in slot 810 integral with the drive pin, the arm coupler pushesdown against spring 504.

To place the bone stock to be cleaned in module 602 it is necessary tolift the shell 650 off the module base 604. To remove the shell 650, thelatch 880 is rotated to the unlocked state. This would mean rotatinglatch 880 counterclockwise as the latch is viewed in FIG. 1. Thisrotation of the latch through the engagement of tab 886 against mortise826 results in a like rotation of the lock plate 818. As a result ofthis rotation of the lock plate 818, the lock plate tabs 822 rotateclear of the tabs 653 integral with shell 650. This allows the shell tobe removed from the base 604.

A further result of the rotation of the lock plate 818 is that magnet848 rotates away from sensor 586. In many versions of the invention, themotor controller 596 is configured to allow the motor 140 to be actuatedwhen a signal from a single one of the sensors 586 or 587 indicates thatthere is a magnet in close proximity to the sensor. When the lock plate818 is in the unlocked position no magnet adjacent either sensor 586 orsensor 587. This means that depressing of either switch 588 or 590 willnot result in the actuation of the motor 140.

Also as a result of the rotation of lock plate 818, atoll 828 integralwith the lock plate rotates so atoll surface 829 is rotated against oneif not both of the toes 808 of the drive pin 802. The rotation of thetoes 808 results in a like rotation of the drive pin 802 and, byextension, the pivoting of arm 750 and cage 764. Specifically, the cage764 is positioned to the orientation relative to the flutes screw seenin FIG. 77D. As a result of the abutment of the at least one toe 808against atoll surface 829, the drive pin 802 and therefore arm 750 andcage 764 are inhibited from further movement.

When latch 880 is rotated to the unlocked position, further rotation ofthe latch is blocked by the abutment of tab 839 integral with atoll 828abutting the stop 632. When the lock plate 818 is so positioned, rib 634seats in indentation 840 to releasably hold the lock plate, and byextension, latch 880 in the unlocked position.

The bone stock to be cleaned and milled is then placed void space 765internal to the cage 764. Shell 650 is seated back over the module base604. As result of the seating of the shell on the base 604, pin foot 878integral with hub 860 seats in bore 704 internal to the fluted screw690. Latch 880 is rotated to the position shown in FIG. 1 to return theshell to the locked state. As a result of this rotation of the latchlock plate 818 is rotated to the locked state. Lock plate 818 is rotatedso the lock plate tabs 822 seat over the tabs 653 integral with shell604. This tab-over-tab registration is what releasably locks the shell650 to the base 604.

As a result of the rotation of lock plate 818, the lock plate atoll 828assumes the orientation relative to toes 808 integral with drive pin 802as seen in FIG. 74. More specifically the atoll 828 spaces away from thetoes 808. This means the drive pin and by extension arm 750 and cage 764are free to rotate.

When latch 880 is rotated to the locked position, further rotation ofthe latch is blocked by the abutment of tab 839 integral with atoll 828abutting the stop 638. When the lock plate 818 is so positioned, rib 636seats in indentation 840 to releasably hold the lock plate, and byextension, latch 880 in the locked position.

The rotation of the lock plate 818 to the locked position also resultsin the rotation of magnet 848 so the magnet rotates over sensor 586.Sensor 586, in turn, outputs a signal to the motor controller 596indicating a magnet is in the presence of the sensor. Motor controller586 interprets this signal as indicating that assembly 100 is in a statein which the cleaning module 602 is attached to the base and the moduleshell 650 is locked to the module base 604. When the motor controller596 determines assembly 100 is in this state, the controller actuatesLED 588, the LED adjacent switch 586. This provides a visual indicationthat the switch that needs to be depressed to actuate the assembly isswitch 586, the switch used to start the cleaning process.

Once switch 586 is depressed, the motor controller 596 actuates themotor 140 for a set period of time. Often this period of time is between3 and 20 minutes. As discussed below, the actuation of the motor 140results in a like rotational movement of the three couplers 194, 348 and486. When the primary coupler 194 is rotated, spring 214 urges thecoupler teeth 202 into the notches 702 of the overlying fluted screw690. The fluted screw 690 thus rotates in unison with the primarycoupler 194. Spring 394 urges the tube coupler 348 upwardly so thecoupler teeth 353 seat in the notches 718 associated with the tumbleplate 710. This tooth-in-slot engagement causes the tumble plate andshaving tube to rotate with the tube coupler. Spring 504 causes bar 492of the rotating cage coupler to seat in the slot 810 integral with drivepin 802. The drive pin thus transfers the rotational motion of the cagecoupler to arm 750 and cage 764.

The actual bone cleaning process consists of plural cleaning cycles.Each cycle consists of a set of phases. In this version of theinvention, the motor 140, through gear train 144 and the spindle 170continually rotates the primary coupler 194. Fluted screw 690, which isconnected to the primary coupler 194, rotates with the primary coupler.The fluted screw 690 rotates even in the some of the below describedphases in which the rotation of the screw may not contribute to the bonecleaning process.

The rotational movement of the spindle 170 is transferred through thegear train 220 to the arm cam 234 and the clutch cam 252. The arm cam234 rotates in a counterclockwise when looking at the view of the campresented in FIG. 75. The clutch cam 252, when looking at the view ofthe cam as presented in FIG. 76, also rotates counterclockwise.

A first phase of a cleaning cycle is the press phase. In the pressphase, the inner lobe 258 of the clutch cam 252 rides against pawl 396.In FIG. 76, the roller 412 of pawl 396 is represented by a triangle.This means the clutch is in the disengaged state. Tumble plate 710 andthe shaving tube 724 therefore do not rotate. Simultaneously, the outerlobe 238 of the arm cam rotates against the rocker arm 508. In FIG. 75,the roller 524 of rocker arm 508 that bears against arm cam 234 isrepresented by a circle. As a result, the rocker arm 508, and crank 448cooperate to hold the shaft 422 in specific rotational orientation. Thisspecific rotational orientation, as the orientation that, as representedby FIG. 77A being the orientation in which the cage is positioned sopress block 772 is directed towards the window 728 internal to theshaving tube 724.

As a result of the cleaning module 602 having cycled through the belowdescribed sweep phase of the previous cycle, the bone chips beingcleaned were previously collected in the cage void space 765 adjacentthe press block 772. As discussed below the press block 772 ispositioned to be located relatively close to the shaving tube window728. A benefit of this close positioning of the press block to thefluted screw and shaving tube is that it increases the likelihood thatthe bone stock will be pressed against the fluted screw 690. This meansthat when the cleaning module 602 is in the press phase, the press block772 presses the bone stock through the tube window 728 against therotating fluted screw 690. Soft tissue attached to the bone stockbecomes entrained in the individual rotating flutes 694. The rotatingflutes 694 pull the soft tissue against the cutting edges 726 of theshaving tube 724. This movement of the tissue against the shaving tubecuts the tissue from the bone. More specifically, the movement of therotating cutting edges 696 of the fluted screw against the staticcutting edges of the shaving tube cuts the soft tissue away from thebone stock.

Prior to the cleaning module 602 cycling through an individual pressphase, it is not possible to know the size and shape of the piece orpieces of bone stock that will be pressed by the press block 772 againstthe fluted screw 690. To ensure that press block 772 presses bone stockof varying sizes and shapes against the fluted screw 690, it will berecalled that hat 464 of the cage driver 420 is able to engage in alimited degree of rotation relative to shaft 422. Spring 534 holds thehat 464 in a specific rotational orientation around the shaft 422. Moreparticularly, the spring 534 holds the shaft in an orientation so thatif there is no bone stock against the press block 772, the hat 464, thearm coupler 486, the drive pin 802 and arm 750 cooperate to hold thecage 764 so that the press block 772 is spaced a short distance, awayfrom the shaving tube window 728. In most versions of the invention, thecleaning module is constructed so that if there was no bone stockpresent adjacent the press block, when a cleaning cycle is in the pressphase, the maximum distance between the press block and the outersurface of the shaving tube 724 is 8 mm. More ideally, the maximumdistance between the press block and the shaving tube 724 when no bonestock is present is 4 mm.

When bone stock is sandwiched between the press block 772 and theshaving tube 724, the play between the shaft 422 and the cage 764 meansthat the movement of the cage does not result in an unyielding forceurging the press block into its close proximity position against flutedscrew 690. Instead, spring 534 places a torque on hat 464 that causesthe associated components to in turn place a force on the cage 764. Theforce is placed on the cage to cause the press block 772 to push thebone stock through the shaving tube window 728 and into the rotatingflutes 694. In some versions of the invention, assembly base 102 isconstructed so that the force spring 534 causes the cage 764 to place aforce on the bone stock trapped between the press block 772 and thefluted screw 690 between 8 and 40 Newtons.

During the press phase, the fluted screw 690 is subjected to sideloading. The presence of the static pin 874 in the bore 704 internal tothe screw 690 prevents this side loading from deflecting the flutedscrew 690 to the point at which the flutes 694 start to scrape againstthe inner surface of the shaving tube 724.

The press phase is followed by the tumble phase. The assemblytransitions from the press phase to the tumble phase as a result of theclutch cam 252 rotating so that the cam outer lobe 262 rotates againstthe pawl 396. The resultant pivoting of the pawl away from tab 304shifts the clutch to the engaged state. The tumble plate 710 and shavingtube 724 therefore rotate simultaneously with and in the same directionand at the same speed as the fluted screw 690. The outer lobe 238 of thearm cam 234 continues to rotate against the rocker arm 508. Thus, thecage remains in the same position relative to the shaving tube as whenmodule was transitioning through the press phase.

As a result of the rotation of shaving tube 724, the tube rotates thebone stock disposed in the tube window in the counterclockwise directionin the representation of FIG. 77B. This clears the bone stock out of thespace between the shaving tube 724 and the press block 772.

During the tumble phase, the rotation of the tumble plate 710 may assistin the tumbling of the bone.

A shift phase follows the tumble phase. The transition to the shiftphase occurs when the linear surface of the arm cam 234 between theouter lobe 238 and the inner lobe 242 rotates against the rocker arm508. The resultant pivoting of the rocker arm 508 causes the cage driver420 to pivot the cage 764 so that the press block 772 moves away fromthe fluted screw 690 and rib 780 moves towards the fluted screw as seenin FIG. 77C.

During the shift phase, outer lobe 262 of clutch cam 252 continues toride against pawl 396. Tumble plate 710 and shaving tube 724 continue torotate. The rotation of these components of the cleaning module duringthe shift phase may not appreciably contribute to the cleaning of thebone.

As depicted in FIG. 77C, during the cleaning process, a piece of bonestock may become caught between the relatively fast rotating flutedscrew and the slower rotating shaving tube 724. This event occursbecause a tail of soft tissue may be drawn into the tube window 728 andwrap around the fluted screw 690. If the tissue does not catch on aflute 694, the tissue may not be pressed against the cutting edge 726with the force needed to cause the severing of the tissue.

Once rotation of the arm cam 234 results in the cam inner lobe 242riding against the rocker arm 508, the assembly of this invention entersthe clear and gather phase. During the clear and gather phase, outerlobe 226 of clutch cam 252 continues ride against pawl 396.

Thus during the clear and gather phase, rib 780 is in close proximity tothe fluted screw and shaving tube. The fluted screw, the tumble plateand the shaving tube continue to rotate. As a result of the rotation ofthe tumble plate, the bone stock is rotated towards the inner surface ofcage panel 770 as seen in FIG. 77D. Rib 780 thus functions as acomponent of the cleaning module that facilitates the clearing oftrapped bone stock away from the cleaning assembly, the fluted screw andthe shaving tube.

As a result of the rotation of the shaving tube, bone stock caughtbetween the fluted screw and the shaving tube is rotated against rib780. Most often, the bone stock is rotated against surface 782. The bonestock travels downwardly along surface 782. As the bone movesdownwardly, the tail of tissue is pressed against the cutting edge of726 of the rotating shaving tube 724. The result of this cuttingedge-against-tissue action is the cutting of the tissue away from thebone stock. The bone stock is thus cut free from the fluted screw 690.

The last phase of a single cleaning cycle is the sweep phase. As aresult of the rotation of the clutch cam 252, the cam inner lobe rotatesagainst pawl 396. Tab 304 is then forced back against the pawl 396. Thisreturns clutch 278 to the disengaged state. The tumble plate 710 andshaving tube 724 therefore stop rotating. More specifically, when thisevent occurs, the shaving tube 724 needs to have so the press block canbe directed towards the window 728 in the following press phase.

Also during the sweep phase, as a result of the rotation of the arm cam234, the cam transition surface between the inner lobe 242 and outerlobe 238 rotates against rocker arm 508. Cage driver 420 thus pivots thecage 764, as represented by FIG. 77E, so the press block 772 is againpositioned back to the position when in the press phase as representedby FIG. 77A. As a result of this motion of the cage 764, the cage pushesthe bone stock disposed against panel 770 against the shaving tubewindow 728. Thus at the end of the sweep phase the bone stock is againpressed by the press block 772 against the window of the shaving tube.

The completion of the sweep phase concludes the movement of the cleaningmodule components through a single cleaning cycle. The assembly thencauses the cleaning module to advance through the press phase of thesubsequent cleaning cycle.

In some versions of the invention, a single cleaning cycle lasts between3 and 20 seconds. The press phase lasts between 25 and 50% of the cycle.Ideally, during a single press phase, the fluted screw should engage inat least four 360° rotations if not at least six rotations. The tumblephase occupies between 10 and 40% of a single cleaning cycle. In asingle tumble phase, the shave tube should engage in at least twocomplete rotations if not three or more complete rotations. The clearand gather phase typically occupies between 5 and 20% of a singlecleaning cycle. The shift and sweep phases each occupy between 5 and 15%of a single cleaning cycle. In some versions of the invention once theassembly is actuated to clean the bone stock, the assembly remainsactuated for a period between 3 and 20 minutes. Often the assembly 100is actuated for a period between 5 and 20 minutes. In many versions ofthe invention, the assembly is actuated for a period of between 8 and 15minutes.

After the motor controller 596 deactivates the motor 140, the cleaningmodule 602 is removed from the base. This activity is accomplished bymoving the latch assembly 540 to the unlatched state. This isaccomplished by depressing to the finger grips 562 towards each other.Finger force it is understood is sufficient to overcome the force thatthe spring 566 places on the plates 542 and 544 to hold the latchassembly in the latched state. The movement of the finger grips resultsin the like movement of plates 542 and 544. The movement of plates 542and 546, pivots plates 546 and tabs 548 pivoted inwardly. The pivotalmovement of the tabs 548 retracts the tabs from slots 612 so as to placethe latch assembly 540 in the unlatched state. At this time, thecleaning module 602 can be removed from the assembly base 102.

Milling module 902 is then seated over the assembly base 102. The latchassembly 540 is used to hold the milling module 902 to the assembly base102 the same way the assembly 540 is used to hold the cleaning module602 in position. Latch assembly tabs 548 extend through the openings 908in the bottom shell 904 of the milling module 902. When the millingmodule is so secured to the assembly base 102, the underside of theassembly stem 966 is disposed above the primary coupler. At a minimum,coupler pin 198 seats in stem bore 974. The bottom end of sleeve 926 isdisposed over the tube coupler 348. The arm coupler 486 seats in opening932 in the underside of the bottom shell as seen in FIG. 78.

The cleaned bone stock is then transferred to the miller hopper 952.This process starts with the unlatching of shell 660 from the rest ofthe cleaning module 602. As a result of the rotation of latch 880, thelock disc 818 returns to the rotational position of FIG. 73. Themovement of the lock disc results in the pivoting of the drive pin 802.The pivoting of the drive pin result in the like pivoting of arm 750 andcage 764. The cage 764 is pivoted to the orientation as seen in FIG.77D. Here the cage 764 is located so the press block is located more tothe perimeter of the tumble plate 710 and spaced away from the flutedscrew 690.

When cage 764 is in this orientation, the cleaning module 602 is broughtto the open end of the hopper 952 and the end of the cage adjacent tab792 is directed to the hopper. With the assistance of gravity, thecleaned hone stock is then transferred into the hopper 952. Once thetransfer is complete, the plunger 953 is placed in the hopper.

When the milling module 902 is seated over the assembly base top plate122, and the catch tray 980 is latched in module opening 924, magnet1010 is disposed over sensor 587. The sensor 587 therefore outputs asignal to the motor controller 596 indicating that this field is sensed.Motor controller 596 interprets the presence of this signal asindicating the milling module 902, including the catch tray 990, in thecorrect position for the milling process to proceed. Motor controllerthen actuates the LED 591 associated with switch 590.

To mill the bone, switch 590 is depressed. When assembly 100 is soconfigured to mill hone, the motor controller 596 actuates the motor foras long as the switch 590 is depressed. The resultant rotation of theprimary coupler 194 results in the rotation of a milling component suchas the cutting disc 958. While the cutting disc 5958 is rotated, theperson performing the milling process presses down on the plunger 953.The bone stock is pushed against the rotating cutting disc. The cuttingelements urge the hone stock against the impingement plate 984 so as toresult in the hone stock being sheared into hone chips. The bone chipsfall through the openings 963 in the cutting disc and into the catchtray 988.

At the completion of the milling process the catch tray 988 is removedfrom the milling module 902. The bone chips are available for use in theprocedure in which the use of the chips is required.

As a result of the removal of the catch tray 988 from the milling module902, the magnet 1010 is withdrawn away from the complementary sensor587. The sensor 587 therefore stops asserting the signal to the motorcontroller 596 that a milling module 902 with latched catch tray 988 isattached to the assembly base 102. As a result of the change in signalfrom sensor 587, the motor controller 596 no longer actuates the motor140 upon the depression of switch 590.

Assembly 100 of this invention thus provides a means to first clean andthen mill freshly harvested bone stock that requires only minimal humancontact with the bone stock. The bone cleaning module 602 is designed toremove the soft tissue that is often attached to this bone stock. Module602 is designed so that if during the cleaning process, the bone stockgets hung up between the fluted screw and the shaving tube thecomponents of the module cooperate to shear the bone stock from thesecomponents. Bone cleaning module 602 is further configured to, betweenthe pressing phases in which cleaning typically occurs, tumble the bonestock. This appreciably increases the likelihood that the exposedsurfaces of each piece of bone stock will be pressed against the flutedscrew and the shaving tube. Increasing the likelihood that each piece ofbone stock is so positioned results a like increase in the thoroughcleaning of each piece of bone stock.

To ensure the bone stock is so cleaned, the presence of indention 769 inthe cage provides the cage with a void space 765 such that there issignificant space adjacent the press block 772. The advantage of thelarge amount of space adjacent the press block facilitates thedislodgement of the bone away from the fluted screw and the shaving tubeduring the tumble phase. Then, during the sweep phase, the presence ofindention 769 means that the distance between panels 768 and 770 of thecage is smaller than it would be if indentation 769 was not present.This means that the tumbled bone is contained in small space. Thisincreases the extent to which the bone, during the sweep phase, isgathered and directed towards the fluted screw for the next press phase.

Still a further feature of the cleaning module of this invention is thattissue excised from the bone is augered into the catch space 682associated with the module shell 650. This means that person performingthe cleaning process does not have to be concerned with collecting anddisposing of this waste material.

The bone cleaning module 602 of this invention is further designed, sothat after the cleaning process, upon removal of the shell 650, the cageis held a specific position relative to the fluted screw 690 and shavingtube 724. More particularly, the cage 764 is positioned so as tofacilitate the gravity assisted transfer of the cleaned bone stock intothe milling module 902.

VI. Alternative Cleaning Module Features

FIG. 86 depicts the inside features of an alternative cleaning module1250 of this invention. Module 1250 includes many of the same basiccomponents as the cleaning module 602. Accordingly, these components arenot redescribed. One difference between the two modules is the structureof the arms. Module 1250 includes an arm 1252 and a cage 1254. Arm 1252is substantially identical in shape and function to arm 750. Cage 1254extends from arm 1250. A difference between the two assemblies is thatin the comparison of the assemblies of FIGS. 54 and 86, cage 764 extendsoutwardly to the right of arm 750; cage 1254 extends to the left of arm1252. Cage 1254 includes panels 1255, 1256 and 1257. Panels 1255, 1256and 1257 are analogues to, respectively, panels 766, 768 and 770 of cage764. Not seen in the press block between the corner formed by wherepanels 1256 and 1257 meet.

Cage 1254 is further formed to have a ramp 1258. The ramp 1258 protrudesinwardly from panel 1255. Ramp 1258 includes an inclined surface 1259analogues to surface 782 of rib 780, ramp surface not identified.Surface 1259 extends upwardly from panel 1255 to the corner betweenpanels 1255 and 1257. Module 1252 includes cage 1254. As rib 1258extends upwardly, the width across the base of the rib decreases. Cage1254 is further formed to have a tab 1260 that projects inwardly fromtop of panel 1257. Tab 1260 is located over a section of the panel 1257from which rib 1258 extends downwardly. The tab 1260 extends inwardlybeyond the apex of rib 1258.

Module 1252 also includes the shaving tube 1264 seen best in FIG. 87.Shaving tube 1264 includes the features of the previously describedshaving tube 724 of FIG. 46. Shaving tube 1264 is also formed to have atleast one pin 1266, two pins 1266 shown. The pins 1266 extend radiallyoutwardly from the outer surface of the shaving tube 1266. Not seen arethe bores in which the pin 1266. The shaving tube 1264 is constructed sothe pins 1266 extend outwardly from a location more towards the top thanthe bottom of the shaving tube. The pins 1266 extend outwardly from asection of the shaving tube opposite the section of the tube in whichthe window 722 is formed. The pins 1266 are positioned to rotate throughan area above the press block and that is adjacent the ramp 1258.

FIG. 88 illustrates the hub 1270 of cleaning module 1262. While theresome aesthetic differences, hub 1270 includes the base 862, stanchions870 and webs 872 of hub 860. A pin 1272 extend downwardly from wherewebs 872 meet. A foot 1278 extend downwardly from the free end of pin1278. Pin 1272 and foot 1278 are not cylindrical in shape. Instead boththe pin 1272 and foot 1278 are formed with longitudinally extendingindentations. The pin 1272 and foot 1278 perform the same generallyfunction as, respectively, pin 874 and foot 878 of hub 860.

The hub 1270 is further formed to have plural fins 1274 that extendradially outwardly from the pin 1272. In the illustrated version of theinvention, the hub 1270 is formed with three equangularly spaced apartfins 1274, two fins identified. In the depicted version of theinvention, each fin 1274 is in the shape of elongated tubularly shapedrod. The fins 1274 extend outwardly from the portion of the pin 1272above the hub base 862. While the fins 1274 extend radially outwardlyfrom pin 1272, the fins are not linear in shape. Instead the fins 1274are curved. As each fin 1274 extends radially outwardly, the fin tinescurve to the adjacent tine. Each fin 1274 curves in the same direction.The cleaning module 12672 is configured so that the curve of the fins1274 is in a direction that is opposite the direction in which thefluted screw 690 rotates during the cleaning process.

When cleaning module 1262 is assembled, hub 1270 substitutes for thefirst described hub 860. Foot 1278 seats in bore 704 formed in thefluted screw 690. Since the fins 1274 are located above the base 862 ofthe hub 1270, the tines are located above the shaving tube and thefluted screw. The components forming the cleaning module 1274 are shapedso that fins 1274 are located above the shaving tube 724.

Bone stock is cleaned using module 1262 in the same generally way inwhich the bone stock is cleaned using module 602. In versions of theinvention that employ cleaning module 1262 the complementary base isconfigured to rotate the shaving tube 1264 clockwise from theperspective of the tube seen in FIG. 86. One difference between the twocleaning processes occurs during the clear and gather phase. When module1262 is employed to clean bone, the movement of the cage 1254 towardsthe shaving tube 1264 during the shift phase is limited by the abutmentof tab 1260 against the shaving tube 1264. This ensures that during thesubsequent clear and gather phase there will be a clearance between thecage 1254 and the shaving tube 1264 that will allow the pins 1266integral with the shaving tube to rotate between the shaving tube andrib 1254. During the clear and gather phase, bone stock trapped by thefluted screw is rotated against the inclined surface 1259 of ramp 1258.Once the movement of the bone stock is blocked by the abutment of thebone stock against the ramp, the shaving tube cuts the bone stock fromthe fluted screw.

During the cleaning process, bone stock may become stuck above the pressblock. The rotating pins 1266 function as wipers against this bonestock. The pins thus wipe the bone stock away from the press block.Gravity causes the bone stock to fall to plate 710. Pins 1266 also wipeaway bone that may be adhering to the ramp 1258. During a subsequentsweep phase this bone stock is forced against the press block so thebone will again be pressed against the fluted screw 690.

The soft tissue cut away from the bone stock is augered upwardly betweenthe fluted screw 690 and the shaving tube 1264. The strands of softtissue rotate against the fins 1274 integral with pin 1272. The fins1274 thus direct the strands of soft tissue radially outwardly from pin1272. This facilitates the movement of the soft tissue away from the hub1270 and towards the outer perimeter of the catch space 682.

Upon removal of the shell 660 with hub 1270 from the rest of thecleaning module 1262, some soft tissue is typically disposed above thefluted screw and shaving tube. Fins 1274 supports these strands oftissue to prevent them from falling out of the catch space 682 and intovoid space in which the cleaned bone stock is located.

VII. Alternative Cleaning Module

FIGS. 79-84 illustrate an alternative arrangement for components of acleaning module 1102 of this invention. Specifically, in this version ofthe invention the cleaning module 1102 has a cage 1202. The cage 1202has three outwardly bowed side walls 1210, one side wall identified thatare connected together to form a triangle. The corners 1211 between theside walls 1210 are rounded, one corner identified. The interior spacebetween the side walls 1210 is the void space 1212 in which the bonestock to be cleaned is deposited. The cage 1210 is open at the bottom.The cage 1210 is further formed so as to have three curved lobes 1203,two lobes identified in FIG. 84. Each lobe 1202 extends outwardly fromone of the corners 1210. A concave shaped transition surface 1204extends between each pair of adjacent lobes 1202, two surfacesidentified in FIG. 84. Each transition surface 1204 is closest to theadjacent side wall 1210 at the mid-point location of the side wallbetween the adjacent corners 121.

The cage 1202 is further formed so that above the lobes 1203 a ring 1206extends radially outwardly from the side walls 1210 and corners 1211.Ring 1206 has a diameter so that the ring is located radially inwardlyfrom the lobes 1203 and extends radially outwardly from the sections ofthe transition surfaces 12-4 closest to the side walls 1210. The ring isformed so to have teeth, not illustrated, that extend around the outercircumferential surface of the ring.

While not seen, it should be understood that the cage may be formed witha features analogues to press block 772 and rib 780. The featureanalogues to the press block functions as the press component of thecage that pushes bone against the fluted screw and shaving tube. Thefeature analogues to rib 780 clears trapped bone tissue from the flutedscrew and shaving tube.

Cage 1202 seats on a circularly shaped disk 1160. Disk 1160 is formedwith a center located through hole 1162. The disk 1160 has three holes1164, 1166 and 1168 that are linearly aligned along a line that extendsradially outwardly from the center of the disk 1160. Hole 1164 islocated closest to the center of the disk 1160. Hole 1168 is locatedfurthest from the center of the disk 1166. Disk 1160 is further formedwith a hole 1170. Hole 1170 is spaced arcuately away from holes1164-1168. Disk 1160 is formed so that hole 1170 is locatedapproximately the same distance from the center of the disc as hole1166.

The cage 1202 is held over the disc 1160 by an arm 1178. Arm 1178 isapproximately teardrop in shape. The widest portion of the arm has athrough hole 1180. Hole 1180 is dimensioned to receive the cage 1202such that the side panels 1210 and corners 1211 of the cage can rotatewithin the hole. Hole 1180 has a diameter that is less than the diameterof the ring 1206 integral with cage 1202.

A pin 1174 extends from disk 1160 to the arm 1178 to hold the arm to thedisk. One end of pin 1174 is mounted in hole 1168 formed in the disk1160. The opposed end of the pin 1174 extends through an opening 1182formed in the narrow width portion of the arm 1178. The componentsforming this bone cleaner are shaped so that the arm 1178 is able topivot freely around pin 1174.

Given that arm 1178 rests on ring 1206 it should be appreciated that thearm is spaced above disk 1160. A gear 1176 is sandwiched between thedisk 1160 and the arm. More particularly, pin 1174 holds the gear 1176to the disk 1160. The gear 1176 is held to the pin 1174 so the pin andgear rotate as a single unit. Teeth, not illustrated, extend outwardlyfrom the outer circular side wall of the gear 1176. The gear 1176 isdimensioned so that teeth of the gear 1176 mesh with the teeth integralwith the ring 1206 that is part of the cage 1202.

This version of the cleaning module of the present invention alsoincludes a roller 1222 that functions as a cam. Roller 1222 is mountedby a pin 1220 to the top surface of disk 1160. Pin 1220 is mounted inhole 1170 internal to the disk. Not illustrated is a spring that urgesthe cage 1202 towards roller 1222. This spring presses the cage 1202towards the roller so that lobes 1202 and transition surfaces 1204 bearagainst the roller 1202.

Cleaning module 1102 includes the fluted screw encased with a shavingtube of the previously described cleaning module 602. In FIGS. 79-82 and85A through 85G the fluted screw and shaving tube are depicted as acylinder 1230. The fluted screw and shaving tube extend through thecenter hole 1162 in the disk. When cleaning module 1102 is assembled,cage 1202 is positioned over the disk so the fluted screw and shavingtube are seated in cage void space 1212.

Disk 1160 and the components mounted to the disc are disposed above astatic cylindrical ring gear 1114, also part of the cleaning module ofthis invention. The disk 1160 it should be understood is disposed abovethe ring gear 1114. Not illustrated are the structural components thathold disk 1160 for rotation above the ring gear 1114. Also notillustrated are the teeth that are formed on the inner surface of thering gear. A drive gear 1108 seen on only in FIG. 80 is disposed in thering gear below disk 1160. The drive gear 1108 may be similar to gear190. Thus, this drive gear 1108 rotates with the spindle that rotatesthe fluted screw. The drive gear 1108 is formed to have a diameter lessthan the diameter of the inner surface of the ring gear 1114.

A planet gear 1110 is rotatingly mounted to the underside of disk 1160adjacent the drive gear 1108. A pin 1112 one end of which is seated indisk hole 1164, rotatingly holds planet gear 1110 to disk 1160. Thecomponents forming cleaning module 1102 are further arranged so that theteeth of the planet gear engage both the teeth of the drive gear 1108and the teeth located around the inside of the static ring gear 1106.Planet gear 1110 is shaped so that the teeth of the gear extend into thevoid space between the top of ring gear 1114 and the underside of disk1160.

Gears 1120 and 1124 are also rotatingly mounted to the underside of thedisk 1160. Gear 1120 is mounted to the disk by a pin 1122 that extendsdownwardly from hole 1160. The components of the cleaning module 1102are arranged so that extends radially inwardly and radially outwardly ofthe top of the ring gear 1114. The portion of gear 1120 disposed withinthe ring gear 1114 engages the teeth of the adjacent planet gear 1110.Gear 1124 is mounted to pin 1174 to rotate with the pin 1174. Gears 1124and 1176 and pin 1174 rotate as a single unit. Gear 1124 is positionedto be driven by gear 1120.

When cleaning module 1102 is actuated, a drive component rotates thefluted screw. An assembly that includes a clutch similar to clutch 278may be employed to periodically rotate the shaving tube. Drive gear 1108is continuously rotated. The drive gear 1108 functions as a sun gear ofa planetary gear assembly. Plane gear 1110 is the single planet gear ofthis assembly. Disk 1160 is the carrier and ring gear 1106 the staticring gear. Thus, as a result of the rotation of drive gear 1108, theplanet gear 1110 rotates around the ring gear 1106. The rotation of theplanet gear 1110 rotates disk 1160 around the center axis of the disk.

Since disk 1160 rotates it should be understood that pin 1174 likewiserotates. This means that the arm or more particularly the outer portionof the arm engages in a rotational motion as seen in FIGS. 85A through85G. By extension this means that the cage 1202 rotates around flutedscrew and shaving tube.

The rotation of planet gear 1110 results in a like rotation of gear 1120and, by extension, gear 1124. The rotation of gear 1124 and thereforepin 1174 rotates gear 1176. Since gear 1176 engages the teeth of ring1206, ring 1206 likewise rotates. Since ring 1206 is part of cage 1202this means that when cleaning module 1106 is actuated, simultaneouslywith disk 1106, cage 1202 rotates within hole 1180 internal to the arm1178.

The biasing member urges lobes 1203 and transition surfaces 1204 againstthe roller 1222. This means that, as the cage 1202 is rotated in the arm1178, lobes 1203 and transition surfaces 1204 are alternatingly urgedagainst the roller. When the lobes 1203 are abut roller 1222, the cageis in the position as depicted in FIGS. 85C, and 85DE, the cage isapproximately centered over the fluted screw and having tube. When thetransition surfaces 1204 abut roller 1222, the cage is positioned asdepicted in FIGS. 85A, 85F and 85G; the cage is positioned so the flutedscrew and shaving tube are located adjacent the inside of one of theside walls 1210 or corners 1211 of the cage. FIGS. 85B and 85F depictintermediate positions of the cage relative to the fluted screw and sidewalls between when one of the outwardly directed lobes 103 or anadjacent or inwardly directed transition surface 1204 is abutting theroller.

Thus in this version of the cleaning module of this invention, theplural movements of the components serve to sequentially cycle the cageso, the corner 1211 of the cage is located adjacent fluted screw andshaving tube as seen in FIGS. 85A and 85G. At this time, the cleaningmodule is in a press phase of a cleaning cycle. Then, as depicted byFIG. 85B, the cage rotates so the inner surface of a side wall 1210 islocated adjacent the fluted screw and shaving tube. The simultaneousrotation of the disk 1160, the rotation of the cage around its own axisand the orbiting of the cage around the center of the disk in FIGS. 85Cthrough 85F can be considered the sweeping of the bone stock for thepress phase of the next cleaning cycle.

VIII. Alternative System Embodiments

The above is directed to specific versions of the invention. Theinvention may have features different from what has been described. Forexample, the features of the different cleaning modules 602, 1102 and1262 may be combined. For example, components similar to press block 772and ribs 768 and 780 may be found internal to cage 1202.

Also, there is no requirement the cleaning modules of this inventionalways be used with the described milling module. Likewise, otherassemblies may be used to clean the bone stock before the milling moduleof this invention is used to convert the bone stock into bone chips.

The features of the different embodiments of the invention may becombined.

Alternative cleaning modules of this invention may have cleaningelements other than the disclosed fluted screw and shaving tube assemblyfor removing the soft tissue from the bone stock. Thus, it is within thescope of this invention that the cleaning element consist of one or morebrushes. Typically these brushes rotate. In these versions of theinvention, the cage is formed with features that facilitate the pressingof the bone stock against the brushes.

The number of and sequence of the phases of a single cleaning cycle mayalso vary from what has been described above. Thus, it is within thescope of this invention that the clear phase, the phase in which thebone stock that is hung up on the cleaning elements is cleared from thecleaning elements may occur between the press phase and the tumblephase. A benefit of this construction of the invention is that all thebone stock, including the bone stock just cleared from the cleaningelements is subjected to tumbling in the tumble phase.

Likewise, in versions of the invention in which the clear phase occursafter the execution of the press phase and the tumble phase, owing tothe construction of the components forming the cleaning module, thefollowing phase may be one in which the bone stock is simultaneouslycleared from the cleaning elements and swept into a section of themodule for the execution of the next press phase. Thus, in this versionof the invention, a cleaning cycle would not have a distinct sweepphase. Similarly, in some versions of the invention, all that occurs inthe clearing phase is the removal of the bone stock from the cleaningelements. In these versions of the invention, the system may beconfigured to prior to the execution of a press phase, execute adistinct sweep phase in which the tumbled bone stock is gathered into asection of the module so, in the press phase the bone stock will bepressed against the cleaning elements.

Similarly, in some versions of the invention, owing to how thecomponents of the cleaning module move, simultaneously with the clearingof the bone stock from the cleaning elements, the bone stock may betumbled. Thus, in these versions of the invention, a single cleaningcycle may consist of: a press phase; a clear and tumble phase; and asweep phase in which the bone stock is gathered for the next pressphase.

Also there is no requirement that in each version of the invention eachcleaning cycle consist of the same sequence of phase phases. Thus, insome versions of the invention the sequential cleaning may includedifferent phases. For example a first cleaning cycle may consist of apress phase and a tumble phase. A second cleaning cycle may consist of apress phase followed by a clear phase. In another alternativeconstruction of the invention, the first cleaning cycle may consist of apress phase and a tumble phase. The second cleaning cycle may consist ofa press phase followed by a clear phase followed by a tumble phase.

The stated dimensions and ratios, unless present in the claims, areunderstood not to be limiting but merely examples.

It may not be necessary for all versions of the invention to have all ofthe described components. For example, it is anticipated that in someversions of the invention the motor internal to the assembly base thatrotates the primary spindle, the arm cam and tube cam may be directlyconnected to the primary spindle 170. In these versions of theinvention, there is no gear train between the motor shaft 145 and theprimary spindle 170.

In some versions of the invention, the pin that holds the fluted screwsteady may be formed integrally with the cap that extends over theopening in the shell through which the excised soft tissue is augered into the catch space. Thus, in these versions of the invention, it is notnecessary to provide a hub for holding this pin static relative to therest of the cleaning module.

In alternative versions of the invention, assemblies other than thedescribed clutch cam and arm cam may be employed to ensure that, duringa cleaning cycle, the components of the cleaning module move in theproper sequence to ensure the bone stock is subjected to each of thecleaning phases. Thus, in one alternative construction of the invention,gear trains are incorporated to the base 102 to drive the order toensure that during a cleaning cycle, the couplers 194, 348, 486 in theappropriate sequence. In these versions of the invention, one or morecams may be integral to the gear trains. These cam may rotate aroundaxes that are no concentric with the axis around which the primaryspindle 170 rotates.

Still other versions of the invention may not include cams andassociated followers that employed to ensure the correct sequence ofmovements of the components internal to the bone cleaning module. Insome versions of the invention, internal to the base there may be one ormore electrically displaced components. For example solenoids may beused to selectively engage/disengage gears used to drive one or more ofthe couplers 194, 348 and 486.

Likewise, the directions of rotation of the components are understood tonot be limiting but examples. Thus components that move in one directionto accomplish a task, such as the arm cam, the tube cam and rocker armmay move in the opposite directions in other versions of the invention.Likewise, there is no requirement that in all versions of the invention,the components that rotate, rotate in the same direction for each phaseof a cleaning cycle. For example, in some versions of the invention,during the clear phase of a cleaning cycle, the fluted screw and shavingtube may rotate in opposite directions. Further, it is within the scopeof this invention that the sequence of movements of the components maybe different from what has been described. For example, in some versionsof the invention, during the clear phase of a cleaning cycle, the flutedscrew may be static while the shaving tube rotates.

Similarly the drive assembly that moves the press component and theclearing component may not always be configured to displace thesecomponents in a curved path. In some versions of the invention, thedrive assembly may be configured to reciprocate the press component andthe clearing component on a path of travel that instead of being curved,is linear. In these and other versions of the invention the cage thatdefines the press component and clearing component may not completelycircumferentially surround the cleaning elements.

Similarly, the orientation of the components may be different from whathas been described. In some versions of the invention, the fluted screwmay have an orientation other than, relative to the brevity plane,vertical. Thus it is within the scope of this invention that the flutedscrew may have, relative to the gravity plane, an orientation that iseither diagonal or horizontal. In a version of the invention in whichthe fluted screw an, by extension the shaving tube, have thisorientation, a cage similar to cage 1202 may rotate around thesecomponents.

It should thus be appreciated that in alternative cleaning modules ofthis invention the soft tissue that is cut from the bone stock may betransported from the void space in which the cutting occurred to thecatch space along a path of travel other than an upwardly directedhorizontal path. In some versions of the invention, the bone cleaningmodule is constructed so that the soft tissue engages in a path oftravel that relative to the plane of gravity is downward, sideways ordiagonal. If in the gravity plane the catch space is located below thevoid space in which the bone stock is cleaned gravity may at leastpartially assist in the transfer of the cut tissue into the catch space.

Likewise it should be understood that there is no requirement thecleaning module of this invention with the features that facilitate thetransport of the removed soft tissue away from the module componentsthat remove the tissue to the catch space always be used with modulecomponents that cycle the bone stock through each of the above describedpress, tumble, shift, clear and gather and sweep phases.

Thus in one alternative construction of this invention, the cleaningelement consists of a brush. During a press phase a device performs thefunction of the cage and presses the bone stock against the brush as thebrush rotates. In another phase, a ring is forced over the brush. Thering clears entrained bone from the brush and pushes the debris, thesoft tissue, trapped in the bristles of the brush to the catch space.The ring thus functions as the transfer component that moves the excisedsoft tissue into the catch space.

In versions of the invention wherein the cleaning element consists of afirst cutter with a first cutting edge and a second cutter with a secondcutting edge the first and second cutters may be components other than afluted screw and a shaving tube. In this version of the invention one orboth cutters may be blades, each blade having a cutting edge. The driveassembly is configured to move one of the cutters relative to the othercutter so soft tissue is caught and cut between the cutting edges. Aplunger adjacent the cutting edges functions as the transfer componentthat moves the cut tissue from the void space in which the bone stockand cutters are located to the catch space.

In the described version of the invention, the cages that defines thespace in which the bone stock is contained and that pushes the bonestock against the cleaning elements are shown as being shaped so as tofully enclosed the bone stock. This is likewise understood to beexemplary and not limiting.

In alternative versions of the invention sensors other than sensors thatmeasure the presence/absence of a magnetic field may be employed todetermine whether or not the cleaning module is in the locked state or acatch tray is fitted to the milling module. For example, in alternativeversions of the invention, contact sensors may perform this function. Abenefit of this version of the invention is that it the expense ofproviding the cleaning module and milling module with magnets.

In some of the invention some, but not all, of the functions performedby the motor controller are located in the assembly base. Otherfunctions performed by the motor controller are contained in the powerconsole to which the assembly base is attached.

It is therefore the object of the below claims to cover all suchvariations and modifications that come within the true spirit and scopeof this invention.

What is claimed is:
 1. An assembly for milling bone, said assemblyincluding: a shell with an inlet opening configured for depositing ofbone stock and an outlet opening configured for discharging of bonechips; a milling component moveably disposed in said shell between theinlet opening and the outlet opening, the milling component configuredto, when actuated convert bone stock introduced through the inletopening into bone chips discharged through the outlet opening; a catchtray that is removably attached to the shell adjacent the outlet openingto receive the bone chips; and a base to which said shell is removablyattached, the base including a drive assembly configured to actuate themilling component; a sensor is attached to the base, said sensor beingadapted to monitor the shell for the presence/absence of the catch trayand generate a sensor signal that varies as a function of thepresence/absence of the catch tray; and a controller configured toregulate the actuation of the drive assembly based on the sensor signal.2. The assembly for milling bone of claim 1, wherein when the sensorsignal indicates that the catch tray is absent, the controller inhibitsactuation of the milling component.
 3. The assembly for milling bone ofclaim 1 or 2, wherein said sensor is configured to monitor the presenceof a magnetic field and a magnet is mounted to said catch tray.
 4. Theassembly for milling bone of claim 3, wherein when the catch tray ispositioned in the shell and the shell is seated on the base, the magnetis located above said sensor.
 5. The assembly for milling bone of claim1, wherein said sensor is a Hall-effect sensor.
 6. The assembly formilling bone of claim 1, wherein said base includes a motor and whereinactuation of said motor results in like actuation of the millingcomponent.
 7. The assembly for milling bone of claim 6, wherein saidbase includes a control button comprising a contact switch that isconnected to said controller.
 8. The assembly for milling bone of claim7, wherein said switch is adjacent to a light emitting diode (LED) thatis configured to illuminate said switch.
 9. The assembly for millingbone of claim 8, wherein said controller, on receipt of said sensorsignal, is configured to actuate said light emitting diode (LED)associated with said switch to provide a visual indication that saidswitch can be depressed to start milling.
 10. The assembly for millingbone of claim 1, wherein said base includes a base shell having a topplate.
 11. The assembly for milling bone of claim 10, wherein said topplate is formed from material that does not attenuate passage oflocalized magnetic fields.
 12. The assembly for milling bone of claim10, wherein a circuit board is mounted to an underside of said top plateand said sensor is mounted to said circuit board.
 13. The assembly formilling bone of claim 10, wherein a latch assembly is mounted to anunderside of said top plate and releasably holds said base shell to saidbase.
 14. The assembly for milling bone of claim 1, wherein said millingcomponent is a cutting disc.
 15. The assembly for milling bone of claim7, further comprising a cleaning module that can be attached to saidbase when said shell is not attached thereto.
 16. The assembly formilling bone of claim 15, wherein said sensor is also configured togenerate a sensor signal for said controller when said cleaning moduleis attached to said base to allow actuation of said motor.
 17. Theassembly for milling bone of claim 16, wherein said sensor signalfurther activates a light emitting diode (LED) adjacent said switch toprovide a visual indication that said switch can be depressed to startcleaning.
 18. A system for bone preparation, said system including: amilling module comprising: a milling module shell with an inlet openingconfigured for depositing of bone stock and an outlet opening configuredfor discharging of bone chips, a cutting disc moveably disposed in themilling module shell between the inlet opening and the outlet opening,the cutting disc configured to, when actuated, convert bone stockintroduced through the inlet opening into bone chips discharged throughthe outlet opening, and a catch tray that is removably attached to theshell adjacent the outlet opening to receive the bone chips; a cleaningmodule comprising: a cleaning module shell including a void space inwhich bone stock to be cleaned is deposited, and at least one cleaningelement disposed in the void space and configured to, when actuated,remove soft tissue from the bone stock; and a base to which the millingmodule or cleaning module is configured to be removably attached, thebase including a drive assembly configured to actuate the cutting discor the at least one cleaning element; a sensor is attached to the base,the sensor configured to monitor the milling module for thepresence/absence of the catch tray when the milling module is attachedto the base and generate a sensor signal that varies as a function ofthe presence/absence of the catch tray; and a controller configured toregulate the actuation of the drive assembly, wherein the controller isconfigured to receive the sensor signal and to, when the milling moduleis attached to the base and when the sensor signal indicates that thecatch tray is absent, inhibit actuation of the cutting disc.
 19. Thesystem of claim 18, wherein the sensor is also configured to generate asensor signal when the cleaning module is attached to the base and allowactuation of a motor of the drive assembly.
 20. A method of bonepreparation with a system for bone preparation including: a millingmodule having a milling component and a catch tray; and a base unithaving a sensor, a controller, and a motor, said method comprising thesteps of: attaching the milling module to the base; generating a sensorsignal from the sensor to the controller when the milling module isattached to the base unit and the catch tray is present in the millingmodule; and regulating actuation of the motor based on the sensorsignal.
 21. The method of claim 20 further comprising the step ofproviding a visual indication on the base that the milling module withthe catch tray present therein is attached and milling can be started.22. The method of claim 20 further comprising the steps of: attaching acleaning module to the base; generating a sensor signal from the sensorto the controller when a cleaning module is attached to the base;regulating the actuation of the motor based on the sensor signal; andremoving the cleaning module from the base.
 23. The method of claim 22further comprising the step of providing a visual indication on the basethat the cleaning module is attached and that cleaning can be started.